i895. RESULTS OF ''CHALLENGER'' EXPEDITION. 63 



6. Among the Nudibranchia collected, a Doridian, Bathydovis 

 (PI. xiv., Fig. 3), possesses a respiratory apparatus composed of many 

 separate " branchial " plumes. This structure, which occurs also in 

 the Hexabranchidae, permits us to affirm that the perianal branchia of 

 the Doridians is formed by the union of many pallial appendages, 

 and in no way corresponds to the ctenidial branchia of other 

 molluscs. 



7. Finally, among Cephalopoda (without trespassing on the 

 special notice by Mr. Hoyle), the capture of a Spirula, one of the five 

 complete individuals known, has been one of the most precious gains. 

 The study of its structure has shown that this form has no relations 

 with the " Calciphora " (Sepia, etc.), or with any Myopsid. Spirula is 

 an Oigopsid, and among them the least removed from the parent stock 

 of modern Dibranchiates. 



Paul Pelseneer. 



The " Challenger " collection of Cephalopoda contained seventy- 

 two species, disposed in thirty genera, of which thirty-two species 

 and four genera were new ; it was only found necessary, however, to 

 create one new family (Amphitretidae). The collection is as 

 remarkable for its deficiencies as for the types represented in it. The 

 rare capture of pelagic forms was probably due to the enormous 

 activity of these animals, which is so great that they can only be 

 captured when the vessel is moving rapidly, a condition unfavourable 

 to the use of the tow-net. A more important means of obtaining 

 them is by the examination of the stomachs of predaceous birds, fish, 

 and cetaceans ; one of the most remarkable items in the collection, a 

 large pen referred to Chiroteuthis, was taken from the stomach of a 

 shark. Science would be greatly advanced if whalers and those 

 engaged in the capture of sea-fowl would preserve the contents of 

 such stomachs in spirit. It is disappointing that not even a fragment 

 of one of the giant squids was found : the largest specimen was the 

 type of Cirrofeuthis magna, which is more than a metre long, and is the 

 largest individual of the genus yet obtained. Neither were the 

 expectations fulfilled of those who hoped that forms hitherto known 

 only as fossils would be among the spoils. Moseley tells us that 

 " even to the last every cuttle-fish which came up in our deep-sea net 

 was squeezed to see if it had a Belemnite's bone in its back " ; but no 

 such precious discovery was made. 



All the specimens of Sepia, including ten new species and some 

 previously known only by their shells, were obtained during the 

 cruise from the Eastern coast of Australia, through the Malay 

 Archipelago, to Japan ; a confirmation of the idea that the Indo- 

 Pacific region is the metropolis of this genus. Great additions were 

 also made to the already large genera Octopus and Loligo ; but these 

 were of less interest than the unique specimens made the types of 

 new genera, each of which presents some character either entirely 

 novel or important as furnishing connecting links between previously 



