236 THE CANADIAN NATURALIST. [JunC 



of species obtained (not including the Nudibraucliiates) was 818. 

 Of these 619 have been identified, the remainino: beino; still un- 

 determined. About 355 have not previously been recorded as 

 from the E-ed'Sea, Of these, 53 species, including three genera, 

 are new to Science, and have been described by Messrs. H. and 

 A. Adams. Professor Issel^ of Genoa, records 640 species as from 

 the Red Sea, and his hst includes 100 new species. Some of 

 these were figured but not described in Savigny's " Description 

 de I'Egypt." JMr. McAndrew dvrelt on the extraordinary dissi- 

 milarity between the Fauna of the Red &'ea and that of the 

 Mediterranean; the number of species common to Japan, the 

 Philippines, Australia, and to the Red Sea, is worthy of further 

 observation. In addition to the Mollusca, a collection of Echino- 

 derms, Crustacea, and Corals, was made and divided among the 

 British, Edinburgh, and Liverpool Museums, The sponges col- 

 lected were sent to Dr. Bowerbank, except one, which had been 

 described by Mr. Carter as a new genus under the name of 



Grayella. • 



On the Structure of the Shell in the Pearly 

 Nautilus. — Mr. H. Woodward. After referring to the great 

 interest attachins: to the Nautilldce on account of their vast 

 geological and geographical range, the author proceeded to des- 

 cribe the structure of the shell with its septa and siphuncle, the 

 latter structure being only found in the Cephalopoda and nearly 

 confined to the Tetrabranchiate division of the class. The cam- 

 erated structure, however, is found both among the Bivalves and 

 Gasteropoda, and the author suggested that if any incipient 

 character could be found leading up as it were to the siphuncle, 

 we might fairly infer that that structure was only a more highly, 

 differentiated form of shell-growth. Such incipient structure 

 occurs in the Ostroeadce and Spondt/lus, in which the shell-muscle 

 dips down from layer to layer, offering a rough similarity to the 

 siphuncle in Aturia and some other Nautili. Mr. AVoodward 

 described the structure of the shell, and showed by actual dissec- 

 tion that no vascular system exists between the shell and the 

 animal by means of the siphuncle. The siphuncle proves only to 

 be a pearly tube, within which is another composed of an exten- 

 sion of the periostracum, and quite destitute of vascular or 

 cellular structure. Shell structure proves, when once formed, to 

 be dead matter, destitute of change, and can only be repaired 

 when in contact with the mantle of the shell. 



