The collections in the Natural History Museum in Rijeka are classified according to systematics, stratigraphy and localities. The Museum houses the Collection of rocks, the Collection of minerals, the General paleontological collection, the Evolution of Man Collection, the Geological stratigraphic collection with specimens from the Rijeka region, the Quartar fossil fauna collection with specimens from the caves of the Rijeka region, the Paleontological collection with exhibits classified per localities, the invertebrates collections, the vertebrates collections and botanical collections.

Collection of Rocks
The Collection of Rocks holds various litospheric rocks systematically arranged into groups of magmatic, sedimentary and metamorphic rocks. All kinds of both, building and decorative stones of the Rijeka region are presented (Jurassic, Cretaceous, Paleogene limestones and breccias; Triassic andesite). The collection holds the oldest object in the Natural History Museum in Rijeka - a specimen of silicic sedimentary rock composed of flint found in 1872 on Iceland. There is also a specimen of travertine, found in 1892 at the Plitivice Lakes, Croatia.
Collection of Minerals

Collection of Minerals
The Collection of Minerals holds various minerals from typical localities in the world, systematically arragned based on their chemical structure. Systematic classification gives an insight into a variety of shapes and sizes of one and the same kind of mineral from different paragenetic localities. Valuable are specimens of different crystals of quartz, specimens of crystals of ore minerals and gemstone jewellery.

General Paleontological Collection
The General Paleontological Collection has a great historic value. Organized according to the rules of biostratigraphy, it consists of fossil specimens the greatest number of which were acquired in late 19th and the beginning of the 20th century on the territory of Austria, Hungary, Czech Republic, Slovakia, Germany, Italy and Greece. The collection also holds some of the oldest specimens in the Natural History Museum in Rijeka: shelly limestone found in Greece in 1875, a cave bear tooth (Ursus spelaeus) found in Czech Republic in 1878, an impression of a laurel leaf (Laurus) found in Germany in 1883, and an impression of a fern leaf (Lepidodendron) found in Jehlcisien in 1890.

Evolution “Evolution of Man”
The Evolution of Man Collection consists of moldings (copies) of the bones of the representatives of the hominid's evolutionary stages (Australopithecus, Homo habilis, Homo erectus, Homo sapiens neanderthalensis), moldings of their artefacts, of the fossil fauna of the period, and original skull bones of modern man (Homo sapiens sapiens).

Geological Stratigraphic Collection of the Rijeka Region
The Geological Stratigraphic Collection of the Rijeka Region holds various rocks and fossils which reveal the litologic structure and biostratigraphy of the deposits of the Rijeka region from the oldest rocks dating back to Carbon to the youngest that sedimented during Paleogene. Important are specimens of ore resources of the Rijeka region.

Collection of Quarternary Fossil Fauna from the Caves of the Rijeka Region
The Collection of Quarternary Fossil Fauna from the Caves of the Rijeka Region holds numerous fossil bones and teeth discovered in 25 caves, thus supporting the diversity of the Peistocene animals. The Collection also holdsawell preserved cave bear skull (Ursus spelaeus ROENMULLER & HEINROTH) found in Sparožna cave in the Kastav area, a skeleton of a fossil brown bear (Ursus arctos LINNE) found in the Baniæ cave on the island of Cres, and artefacts of Peleolithic and Mesolithic cultures.

Paleontological Collection According to Localities
The Paleontological Collection According to Localities was the result of research conducted in Istria, on the Croatian littoral and on the islands of Cres, Krk and Rab. It holds numerous fossil specimens from the Jurassic, Cretaceous, and Tertiary (primarily Paleogene) which document biostratigraphy of the region. Eocene macrofossils from limestone and clastic deposits of the island of Krk, that the collection holds are the most important and of great value for scientific study.

Geological Stratigraphic Collection of the Island of Krk
Within the work on interpretation and revitalization of the natural heritage the Museum has established a regional collection in Dobrinj on the island of Krk: Geological Stratigraphic Collection of the Island of Krk. The Collection resulted from the collaboration between the Museum and Dobrinj municipality. Displayed are 216 specimens of fossil foraminifers (nummulites), corals, bivalves, snails, echinoids, and Paleogene and Cretaceous rocks found of the island of Krk. A geological map, legends and photographs of the finding sites support the original specimens.

Marine Invertebrates Collection
The Marine Invertebrates Collection contains specimens of sponges (Porifera), cnidaria (Cnidaria), polychaetes (Policheta), crustacean (Crustacea), bryozoans (Bryozoa), echinoderms (Echinodermata) and Tunicata. The collection originates from the Hungarian Royal Biological Station that operated in Rijeka in the period 1905 - 1918. Some of the specimens were collected during field research on the Bios research vessel. Since 1987 the specimens have been collected during autonomous diving along the transects. The biological specimens of our collections are stored in the form of wet and dry preparations (animal skeletons). The computer database has been kept since 1997.

Malacological Collection
The Malacological collection holds 10000 specimens of gastropods, bivalvia and cephalopods. The bivalvia collection is, according to experts, a collection of B category, since out of 224 known Adriatic species, after the invertebrate list published in 1997, it contains 135 species from the northern Adriatic, some of them identified in the aquatorium for the first time.
The continual field research to collect specimens for the malacological collection began in 1961 on the island of Rab. It went on until 1982. The research was conducted by Museum's experts independently and in cooperation with the scientists from the Marine Research Center of the Ruðer Boškoviæ Institute in Rovinj. The shallow infralittoral was researched by visual observation method during free diving. Deeper zones were researched by autonomous diving; photo documentation was gathered in association with external experts. Small boats and Vila Velebita, the research vessel, were used to reach the sites. A knife, tweezers, a shovel, a special basket, a sieve to sift the substratum, the bottom grab and the rectangular sledge were used to collect the specimens. Taxonomic determination of the collected material expanded our knowledge of specific species with data on distribution, depths, sea floor characteristics and biometric indicators. Fifteen scientific papers were published. In the island of Rab littoral 83 bivalvia species were determined, and on the islands of northern and central Adriatic, including Rab, the total of 117 bivalvia species were determined. Those specimens formed the basis of the malacological collection and the Museum's curator Mirjana Legac, an expert in mollusks, was listed in the International Directory of Marine Scientists. Within the federal project Organic Production of Marine Ecosystems the Museum curators worked on the Biocenological research on the channel area (the Rijeka bay, the Srednja vrata channel and northern Kvarneriæ). With the Bios research vessel 68 parallel stations on 50 profiles were researched in the period 1965 - 1969. A bottom grab of the Petersen, Van Veen type, a rectangular sledge and a trawlnet were used to collect specimens. Specimens were added to the malacological and ichtiological collections, and Museum's experts were listed in the International Directory of Oceanographers.
A federal project Flora and Fauna of Yugoslavia was conducted within the master project Complex research of the Adriatic. Museum's experts participated in the Flora and Fauna of the Adriatic project in the period 1969-1970. The goal of the project was to solve the basic issues in the research of the Adriatic (inventarization and catalogization). Mirjana Legac, B.Sc. worked on inventarization and catalogization of the bivalves and the cephalopods. For the purpose of the project the Kvarner bay area was researched with the Neverin boat until 1977. The newly acquired data enabled detailed description of the bivalvia and cephalopods of the northern Adriatic, and supplied data on the numerosity, sea floor characteristics and species' distribution. In 1963 the UNESCO international program Man and Biosphere was launched.
In the period 1987 - 1999 the bivalves for the malacological collection were collected during autonomous diving within the scope of Biocenological research of the western coast of the island of Krk, of the Vinodol channel, Rijeka bay, and islands of Goli, Prviæ and Grgur. Since 1997, when Mirjana Legac retired, the curator Milvana Arko-Pijevac, B.Sc. manages the malacological collection. Since 1997 the collection has been entered in ACCESS computer program.

Entomological Collection
Entomological collection was established concurrently with the Museum, by rescuing the abandoned specimens collected by G. Depoli, Goidanich, Hafner, J. Splichai, dr. V. Beszedes, Neuburger, R. Mikšiæ and others. The collection of Guido Depoli was categorized in the A category, and is thus, with the accompanying card files and field work notes, priceless. It presumably contains a number of holotypes from the Coleoptera group. The entomological collection holds 375 entomological boxes and 13 wet preparations with 50 053 specimens.

Ichtiological Collection
Ichtiological collection was, as well as other collections the Museum currently houses, established in 1945 by collecting the specimens of the dissolved Hungarian Royal Biological Station, City Museum (Museo Civico), and various schools in Rijeka. Also, new specimens were added to the collection. In 1992 a curator ichtiologist took over the collection and the number of newly acquired specimens increased rapidly. There are wet and dermoplastic preparations, skeletons or their parts and jaws in the collection. The collections holds about 2000 specimens for 280 species. Especially valuable specimens of the collection are species of goby fish that can only be found in few museums in the world. Among them types of the Gobius kolombatovici Kovačić and Miller species should be singled out. The fish is 10 - 12 cm long, and belongs to the goby family (Gobiidae). It is of characteristic color, and has longitudinally arranged orange spots, with a black spot on the first dorsal fin. In 1998 it was discovered in four localities along the east coast of the island of Krk. It lives at the depth of 15 - 38 meters, on the sea floor composed of detritic sand, fine gravel and stones, most often along steep underwater rocks. Not much is known about the species, as is the case with most of the Mediterranean goby fish, many of which were described already in the 19th century.