LTTSITANIAK- PROYINCE. fi7 



supposed to be now peculiar to tlio Mediterranean ; tlie small 

 number of species sbow tbey are aberrant or expiring forms. 

 Cassidaria, and Thecidium are ancient, "widely-distributed 

 genera, and the Mediterranean Thecidium occurs fossil in 

 Brit! any and the Canaries. 



Tliysanoteutlii^, 2 sp. Scaurgus, 1. MoiTisia, 2. 



Verania, 1. PleurobrancliEea, 1. Thecidium, 1. 



Dosidicus, 1. Tethys, 1, Scaccliia, 2. 



Doridium, 1. Cassidaria, 6 



Icarus, 1. Pediculai'ia, 1. 



The genera ^asce'o/ar/a, Siliquaria, TyJodina, Kotarchus, Verti- 

 cordia ? Clavagella, and Crania, occur only in this portion of tbe 

 Lusitanian province. 



Amongst tbe ^^eculiar species are : — 



Nassa semistriata. Argiope cuncata. Artemis lupinus. 



Fusus crispus. Clavigella angulata. Trigona nitidula. 



Tylodina Rafmesciuii. Spondylus Gussonii. Lucinopsis decusaata. 



Crania rostrata. Astarte bipartita. 



^gean Sea. Prof. E. Forbes obtained 450 species of mollusca 

 in the ^gean, belonging to the follo'^ng orders : — 



Cephalopoda 4 Nudibranchs 1.5 Brachiopoda 8 



Pteropoda 8 Opisthobranchs 23 Lamellibranchs 143 



Nucleobranchs 7 Prosobranchs 217 Tunicata 22 



Of these Yl were new species, but several have since been 

 found in the Atlantic, and even in Scotland.* The only marine 

 air-breather met with was Auricula myosotis. 



Black Sea. In the northern part a few Aralo-Caspian shells 

 are found, otherwise the Black Sea only differs from the Medi- 

 terranean in the paucity of its species ; Dr. Middendorff enume- 

 rates 68 only. The water is less salt, and there is no tide, but 

 a current Hows constantly through the Dardanelles to the 

 Mediterranean, f 



LorenzJ found 178 molluscs at Quarnero, of which 15 were 

 bivalves, and 88 univalves; 75 of them extended their range 

 into the -S^gean Sea, 58 into the Boreal province. Pew only 

 appeared to be peculiar to the Adriatic. 



* Trans. Brit. Assoc, (for 1S43), 1S44, p. 130. 



t A cuiTent from the Atlantic seta in perpetually through the Straits of Gibraltar, 

 and there is scarcely any tide ; it only amounts to one foot at Naples and the Euripus, 

 Iwo feet at Messina, and five at Venice and the Bay of Tunis. 



t Physikalische Verhaltnisse und Vertheilung der Organismen im Quarnerischcn 

 Golfe. Wien, IS63. 



