THE BLACK SEA 



447 



of the Bosporus, including the western part of the Anatolian coast and the 

 southern half of its eastern part. A number of species not found in other parts 

 of the Black Sea have been recorded here. Tuna, swordfish, lobster and a 

 number of invertebrates are fairly common here. An exchange of fauna pro- 

 ceeds continuously between the Black Sea and the Sea of Marmora 

 through the Bosporus. The waters of the Sea of Marmora, carrying its 

 characteristic fauna, penetrate into the Black Sea by the lower current. Such 



Fig. 214. Zoogeographical regions of Black Sea (Yakubova) 

 (see text). 



typical Mediterranean plankton as the Siphonophora Diphyes, the Radio- 

 laria Acanthometra, and the polychaete Tomopteris are found in the Bosporus 

 area of the Black Sea. 



A number of the Mediterranean benthic forms have been discovered in the 

 Bosporus region of the Black Sea, within the sphere of the lower Bosporus 

 currents ; these forms, apparently, do not penetrate very far into the Black 

 Sea (Nikitin, 1927, Jakubova, 1948, Bacesko, 1959). They have been recorded 

 at depths of 38 to 94 m (more than 60 species) and include such forms as the 

 Coelenteratae Phellia elongata and Virgularia mirabilis; the echinoderms 

 Ostergrenia adriatica, Ophiura texturata, Ophiothrix echinata and Cucumaria 

 orientalis ; the molluscs Nucula sulcata, Turitella communis, Murex tareniinus, 

 Venus bragniarti, Nassa incrassata, Corbula gibba, Fissurella graeca, Natica 

 fusca, Gibbula de versa, Schismope stria tula, Cyclonassa brusinai, Pandocia 

 singularis; the worms Phascolosoma minuta, Paronais lira, Proclea graffi, 

 Drilonereis filum, Polidora antennata, Sternaspis scuttata; the crustaceans 

 Cymodoce erythrea euxinica, Elaphognathia monodi, Pontotanais borceai, 

 Colomastix pusillus, Harpinia della-vallei, Philomedes interpuncta, Citereis 

 jonesii ; 20 species of the Foraminifera and many others. They chiefly extend 

 to the north along the western shores of the Sea. 



The Bosporus fauna forms a kind of intermediate link between the faunas 

 of the Black Sea and the Sea of Marmora. 



O. Ostroumov (1894) gave an illustration of this fact, from the example of 

 bivalves, as set out in Table 182. 



