Olszanowski Z., 1996: A monograph of the Nothridae and Camisiidae of Poland (Acari: Oribatida: Crotonoidea). 201 pp. Genus.

 Olszanowski Z., 1997: New oribatid species of the genus Crotonia from Brazil (Acari): Crotonidae). 7 pp. [ARA1698] Genus 8(3-4): 719-725.

 Olszanowski Z., 1997: Trimalaconothrus rafalskii n. sp. – a new oribatid mite species from Poland (Acari: Oribatida: Malaconothridae). 1 pp. [ARA1699] Genus 8(1): 103-108.

 Olszanowski Z., Bromberek K., 2011: Novonothrus lucasi spec. nov., a new moss mite from Australia (Acari: Oribatida: Nothridae). 9 pp. Genus 22(4): 667-675.

 Olszanowski Z., Szywilewska A., Norton R. A., 2001: New moss mite of the Camisia from western Nearctic region (Acari: Oribatida: Camisiidae). 12 pp. (in English). [ARA 1890] [M25] [M26] Genus 12(3): 395-406.

 Olszanowski Z., Szywilewska-Szczykutowicz A., Blaszak C., Ehrnsberger R., 2007: Die Milben in der Zoologischen Staatssammlung München. Teil 10. Überfamilie Crotonioidea (I) (Acari, Oribatida). 9 pp. Spixiana 30(2): 159-167.

 Omoloye A. A., 2010: Effects of genotype variation in the cultivated rice species on the biology and galling characteristics of the African rice gall midge, Orseolia oryzivora (Diptera: Cecidomyiidae). 8 pp. Entomological Science 13(3): 320-327.

 Omori M., Vervoort W., 1986: Observations on a living specimen of the giant hydroid branchiocerianthus imperator. 5 pp. Zoologische Mededelingen 60(16): 257-261.

 Ono H., 1986: Spiders of the families Clubionidae, Gnaphosidae and Thomisidae from the Noto Peninsula and the southern part of Ishikawa Prefecture, Japan. 8 pp. Memoirs of the National Science Museum 19: 167-174.

 Ono H., 1993: Spiders of the genus Clubiona (Araneae, Clubionidae) from Eastern Hokkaido, Japan. 6 pp. Memoirs of the National Science Museum 26: 89-94.

 Ono H., 2001: Crab spiders of the family Thomisidae from the Kingdom of Bhutan (Arachnida, Araneae). 34 pp. Entomologica Basiliensia 23: 203-236.

 Ono H., Hishikawa Y., 1989: Taxonomic revision of the Heptathelid spiders (Araneae, Mesothelae) from Amami-Ôshima Island, the Ryukyus. 7 pp. (in Japanese). Memoirs of the National Science Museum 22: 119-125.

 Ono H., Jocqué R., 1986: Two new species of the family Zodariidae from Saudi Arabia (Arachnida: Araneae). 6 pp. [ARA1700] Fauna of Saudi Arabia 8: 6-11.

 Ono H., Shinkai E., 1988: Notes on the Japanese sandy-beach spider, Lycosa ishikariana (Araneae, Lycosidae), based upon fresh topotypical speciemens. 5 pp. Memoirs of the National Science Museum 21: 131-135.

 Ono H., Tanikawa A., 1990: A revision of the Japanese spiders of the genus Langbiana (Araneae, Zodariidae). 12 pp. Memoirs of the National Science Museum 23: 101-112.

 Oplotna H., Rajski A., 1983: Oppiella rafalskii sp. n. (Acarida, Oribatida). 19 pp. [M18] [M54] Acta zoologica cracoviensia 26/16: 543-562.

 Opravilová V., Vaňhara J., Sukop I., 1999: Aquatic invertebrates of the Pálava Biosphere Reserve of UNESCO. 279 pp.  Discount 20%!

 Opresko D. M., 2001: Revision of the Antipatharia (Cnidaria: Anthozoa). Part I. Establishment of a new family, Myriopathidae. 28 pp. Zoologische Mededelingen Leiden 75(17): 343-370.

 Opresko D. M., 2004: Revision of the Antipatharia (Cnidaria: Anthozoa). Part IV. Establishment of a new family, Aphanipathidae. 31 pp. Zoologische Mededelingen Leiden 78: 209-240.

 Opresko D. M., 2005: New genera and species of antipatharian corals (Cnidaria: Anthozoa) from the North Pacific. 37 pp. Zoologische Mededelingen Leiden 79 (2): 129-165.

 Opresko D. M., 2006: Revision of the Antipatharia (Cnidaria: Anthozoa). Part V. Establishment of a new family, Stylopathidae. 30 pp.  Zoologische Medelingen 80(4): 109-138.

 Opyrchalowa J., Sadkowska H., 1962: Wystepowanie kedzierzawki plaszczyncowej – Beta virus 3 (Wille) Smith oraz zóltaczki wirusowej – Beta virus 4 (Roland et Quanjer) Smith na burakach cukrowych, jako wskaznik pojawu plaszczynca burakowego – Piesma quadrata Fieb., i mszycy burakowej – Aphis fabae Scop., w województwie wroclawskim w r. 1961. 11 pp. 

 Ortega I., Díaz Y. J., Martín A., 2010: Feeding rates and food preferences of the amphipods present on macroalgae Ulva sp. and Padina sp. Tasas de alimentación y preferencias alimenticias de los anfípodos presentes en las algas Ulva sp. y Padina sp. 9 pp. Zoologica Baetica 21: 45-53.

 Oschmann M., 1999: Verbreitung von Gallmilben (Acari) in Westthüringen. 7 pp. [ARA 1402] Thüringer Faunistische Abhandlungen 6: 61-67.

 Oshiro L. M. Y., 1999: Aspectos reprodutivos do caranguejo guaia, Menippe nodifrons Stimpson (Crustacea, Decapoda, Xanthidae) da Baía de Sepetiba, Rio de Janeiro, Brasil. 8 pp. Revta bras. Zool. 16(3): 827-834.

 Ossiannilsson F., 1966: Making permanent fluid mounts of minute arthropods. 5 pp. (in English). Entomologisk Tidskrift 87(1-2): 1-4.

 Oštrec L., 1971: Fauna Oribateia u oraničnim tlima istočne Hrvatske. (I prilog poznavanju Oribateia Hrvatske). 6 pp. 

 Oštrec L., 1975: Oribatide u šumskim tlima borovca (Pinus strobus). 5 pp. 

 Oudemans A. C., 1910: Notes on Acari. XIXth series. (Acaridae). 18 pp. 

 Oudemans A. C., 1926: Chorioptes caprae (Del. Bourg. 1858). 22 pp. 

 Oudemans A. C., 1927: Laelaps-Studien. 47 pp. 

 Oudemans A. C., 1936: Neues über Pediculoides Targ. Tozz. 1878. 14 pp. 

 Ovtsharenko V. I., Fet V. Ya., 1980: Fauna and ecology of spiders (Aranei) of Badhyz (Turkmenian SSR). 6 pp. (in Russian). Entomologitsheskoe obozrenie 59(2): 442-447.

 Ovtsharenko V. I., Marusik J. M., 1990: Taksonomičeskie zamečanija o paukach (Aranei), opisannych A. Grube. 4 pp. 

 Ovtsharenko V. I., Saveljeva L. G., 1990: Analiz fauny paukov semějstva Gnaphosidae Vostočnogo Kazachstana. 3 pp. 

 Paclt J., 1951: Contribution a l’etude de notre faune de domaine principalement endoge. I. 4 pp. (in Czech). 

 Paclt J., 1951: Contribution a l’etude de notre faune de domaine principalement endoge. I. 4 pp. (in Czech). [EVE 551] Folia entomologica 14: 161-164.

 Paladian G., 1965: Some Chromadoridae (free-living Nematoda) from the rocky facies of the Black Sea (Rumanian shore). 6 pp. 

 Paladian G., Lazarescu D., Muresan A., 1968: Biological effects of water-courses pollution of the Ialomita hydrographic basin. 6 pp. 

 Páll-Gergely B., 2010: Montenegrina dofleini sinosi n. ssp. from north-western Greece (Gastropoda: Pulmonata: Clausiliidae). 5 pp. Genus 21(1): 149-153.

 Palmén E., 1946: Die Landisopoden Finnlands. 35 pp. 

 Palmén E., 1946: Zwei aus Finnland bisher unbekannte Synanthrope Land-Isopoden. 2 pp. 

 Palmén E., 1951: A survey of the Oniscoidea (Isopoda terr.) of Newfoundland. 27 pp. 

 Palmén E., 1954: Seasonal occurrense of Ephyrae and subsequent instars of Aurelia aurita (L.) in the shallow waters of Tvärminne, S. Finland. 9 pp. (in English). Arch. Societatis Zoologicae Botanicae Fennicae Vanamo: 123-131.

 Palmén E., Rantala M., 1954: On the life-history and ecology of Pachymerium ferrugineum (C. L. Koch) (Chilopoda, Geophilidae). 44 pp. 

 Pana I., 1968: Especes du genre Paradacna dans les dépots pliocenes de la courbure des Carpathes. 9 pp. 

 Pande Y. D., Berthet P., 1975: Observations on the vertical distribution of soil Oribatei in a woodland soil. 17 pp. 

 Pandourski I., 1992: Acanthocyclops (Acanthocyclops) iskrecensis sp. n. (Copepoda, Cyclopoida) des eaux souterraines de la Stara Planina d’ouest (Bulgarie). 5 pp. (in French). Bolletino del Museo regionale di Scienze Naturali – Torino 10(2): 401-405.

 Pandourski I., 1997: Composition, origine et formation de la faune cyclopidienne stygobie de Bulgarie et définition du groupe d’especes „kieferi“ du genre Acanthocyclops (Crustacea, Copepoda, Cyclopoida). 19 pp. (in Italy). Bolletino del Museo regionale di Scienze Naturali – Torino 15(2): 279-297.

 Pankratova V. J., 1959: Litshinki tendipedid nekotorych rek Krasnodarskogo kraja. 10 pp.