LUSITANIAN PROVINCE. 67 
supposed to be now peculiar to the Mediterranean ; the small 
number of species show they are aberrant or expiring forms. 
Cassidaria, and Thecidiwm are ancient, widely-distributed 
genera, and the Mediterranean Thecidiwm occurs fossil in 
Brit‘any and the Canaries. 
Thysanoteuthis, 2 sp. Sceurgus, 1. Morrisia, 2. 
Verania, 1. Pleurobranchea, 1. Thecidium, 1. 
Dosidicus, 1. Tethys, l. Scacchia, 2, 
Doridium, 1. Cassidaria, 6 
Icarus, 1. Pedicularia, 1. 
The genera Fasciolaria, Siliquaria, Tylodina, Notarchus, Verti- 
cordia 2 Clavagella, and Crania, occur only in this portion of the 
Lusitanian province. 
Amongst the peculiar species are :— 
Nassa semistriata, Argiope cuneata. Artemis lupinus. 
Fusus crispus. Clavigella angulata. Trigona nitidula. 
Tylodina Rafinesquii. Spondylus Gussonii. Lucinopsis decussata. 
Crania rostrata. Astarte bipartita. 
Aigean Sea. Prof. H. Forbes obtained 450 species of mollusca 
in the Aigean, belonging to the following orders :— 
Cephalopoda ...........006 4 Nudibranchs ..... Meek BrachiOpodaincascreseevesesaats 
IEHETOPOU Bi seeresscscaccsves ss 8 Opisthobranchs...... 28 Lamellibranchs ......... 143 
Nucleobranchs ..........+. 7 Prosobranchs ......... 217 CUDTOVCERT) ‘Soncconsdoocces co 22 
Of these 71 were new species, but several have since been 
found in the Atlantic, and eyen in Scotland.* The only marine 
air-breather met with was Auricula myosotis. 
Black Sea. Inthe 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 flows constantly through the Dardanelles to the 
Mediterranean. t+ 
Lorenz{ found 178 molluscs at Quarnero, of which 75 were 
bivalves, and 88 univalyes; 75 of them extended their range 
into the Aigean Sea, 58 into the Boreal proyince. Few only 
appeared to be pecuhar to the Adriatic. 
* Trans. Brit. Assoc. (for 1243), 1844, p. 180. 
tf Accurrent from the Atlantic sets in perpetually through the Straits of Gibraltar, 
and there is scarcely any tide ; it only amounts to one foot at Naples and the Euripus, 
two feet at Messina, and five at Venice and the Bay of Tunis. 
t Physikalische Verhaltnisse und Vertheilung der Organismen im Quarnerischen 
Golfe. Wien, 1863, 
