117 



in the Coralline tone ; but their favourite haunts bare not been made 

 known. Of these, the C. trachea is recorded as J " — i 1 in the Sub- 

 appenine beds. 



On reaching the Cauaries, we lose the European species; but at 

 the great depth of 50 fathoms Mr. M' Andrew dredged many hun- 

 dreds belonging to five species or varieties of the dnellum and Far- 

 tulum groups. They were all pure white and very fresh ; but most 

 were pierced by Proboacidifers, and nol one was found with ii > 

 operculum. It is doubtful, therefore, whet her the gravel-sand was 

 their place of residence. No species has yet been found either on 

 the (riiinea Coast, at the Cape, or at Port Natal. 



The tropical regions of America -appear to be the bead-quarters 

 of the group, both for the number of species and of bdiviuals. The 

 only species which has been found living adheres to groups of Ver- 

 meti in the Laminarian zone. But the coarse sponge of commerce, 

 known to be from the West Indian region by the shells which are 

 found abundantly in it, as well as from the same Coca being ob- 

 tained in shell-sand from the Antilles, has supplied the principal 

 part of the Atlantic species. Although most of the shells are dead, 

 enough have been found with their opercula to prove that they live 

 at no great distance. Here we find the handsome group EUphan- 

 tulum ; here the most delicately sculptured forms in each division ; 

 and here the abnormal genus Meioceras, presenting in the mode of 

 growth a singular approach to Vermetus. It is remarkable thai 

 the type of this genus is also found fossil in Barbadoes, both in its 

 young and adult state, in company with species still living in the 

 island, but now of smaller size (Dr. Cutting). The European types 

 are both found here sparingly ; but whether they are conspeciiic is 

 not yet decided. 



On crossing the peninsula, we find eighteen species belonging to 

 the three groups of Ceeca, all of which can be easily separated from 

 the (perfect) West Indian forms. Here again the "analogue " of 

 Brochina glabra occurs in limited numbers; of its identity, even 

 generically, it is vain to speak till the opercula have been found. 

 Most of the Mazatlan Ceeca, to the number of at least 1200, were 

 found on breaking up the shells of large Spondyli, &C, where their 

 form is peculiarly adapted to traversing the numerous worm-eaten 

 passages in which they seem to reside *. Numbers were found in 

 every stage of growth (one onlv, however, with the nuclear coils, 

 which are extremely perishable), which materially aided in ascer- 

 taining the principles of specific variation ; and eleven species were 

 found with their opercula, of which some were nearly flat. 



The Indo-1'acific fauna appears as bare of Ceeca a> the American 

 re rich. The C. annulatum reappears at Aden, and the C. re- 

 [Hilar? from Singapore and Australia: from the latter country «c 

 have a new -pecies related to Brockma glabra ; and Japan has re- 

 cently furnished us with two species One at least <l;-t imt . but 



few, however, were found, with their opercula, among thr nod fmni ihr 

 Olivellns, .\r. 



No. CCCLXXIII.— Proceedings oi thkZoologn llS<h i i n 



