ZOOLOGY AND BOTANY, MIOBOSCOPY, ETC. 485 



the darkness. Eesemblances between cave faunas and that of the 

 deep-sea point also to a common cause in the absence of light. The 

 range of some littoral forms into great depths may perhaps be found 

 to be due to their being nocturnal in habits. 



The cavities which occur under coral reefs off Brazil may perhaps 

 shelter a fauna of deep-sea character, owing to the absence of light 

 there; hence it would be not unlikely that geologists might find 

 similar aggregations of deep-sea animals in formations otherwise 

 composed of littoral reefs. Otherwise the relations of deep and 

 littoral faunas were probably much the same in geological times as 

 now, owing to the similarity of their relations to the light, and the 

 differences here indicated can, in point of fact, be traced throughout 

 all formations. 



B. INVERTEBRATA. 



Mollusca. 



Anatomy and Classification of the Cephalopoda.* — Dr. J. 

 Brock commences with a study of Bossia, the knowledge of the 

 anatomy of which is confined to the short description given by Prof. 

 Owen. As a result of the new investigations we find that Bossia is, 

 as has been supposed, most closely allied to Sepiola ; the relations of 

 these two forms to the Myopsida, and especially Sepia and Loligo, are 

 by no means so clear. The author's earlier investigations led him to 

 the belief that the affinities of the different forms might be well shown 

 by this diagram : — 



Sepia. 



— Bossia Sepiola. 



— Loligo. 



— Oiumast replies. 



The presence, however, in Bossia, of fused lower salivary glands 

 points to its affinities with the CBgopsida, and this would lead us to 

 form a table in which Loligo should stand above Rossia, or nearer 

 Sepia. As to the relations of Sepiola to the form last named, it 

 might be supposed that Sejnola had branched off from the Decapod 

 stem independently, but the Octopod characteristics of Sepiola, as 

 seen in its musculature, are to be found also in Bossia, and it requires 

 evidence of a kind very different from that which we have at present 

 to lead us to believe that these very similar arrangements could have 

 been independently developed by the two forms. The Octopod type 

 of the musculature of Bossia is still farther developed in Sepiola, and 

 that in a way which justifies us in regarding the latter as a direct 

 descendant of the former. A useful table is given in which are 

 enumerated twelve characters and the resjiective resemblances and 

 differences of Ommastrephes, Bossia, and Sepiola. 



If the view that Bossia and Sepiola form a line of development 

 which branched off from the Decapod stem shortly before Loligo be 



* Zeitschr. f. wiss. Zool, xxxvi. (18S2) pp. 543-G40 (4 pis.)- 



