iS95. SOME NEW BOOKS. 133 



a woodlouse ; but we are not told, perhaps because the fact was too 

 famihar, how it sticks to its stone like a limpet when one attempts to 

 detach it. 



Chapters x. to xii. give a summary of our knowledge of the 

 geographical distribution of the Mollusca, especially of the land and 

 fresh-water species. The value of this, which is already considerable, 

 might have been increased by a closer attention to the geographical 

 changes of the later geological periods. 



It is, however, when he turns to the deeper questions of 

 morphology and classification, that "the serious student" will have 

 reason to complain of the author's light treatment. Here, indeed, 

 Mr. Cooke reminds us of " the poor cat i' the adage, letting / dare not 

 wait upon / would." All the reviewers in scientific journals have 

 noticed how he admits with Pelseneer that the Pteropoda are related 

 to the Tectibranchiata, being derived from the Aplysioidea and 

 BuUoidea, and how, though he places them in the Opisthobranchs, 

 he nevertheless separates them from their relatives by the pages 

 devoted to Ascoglossa and Nudibranchiata, The Amphineura are 

 retained in the Gastropoda, but the consequent difficulty of drawing 

 up a description of the Gastropoda is evaded by leaving them without 

 a description. The Cephalopoda, too, which strangely are taken 

 first, are given no general definition. " The classification adopted 

 for the recent Cephalopoda is that of Hoyle (' Challenger ' Reports) " 

 (p. v.). Far be it from us to impugn the veracity of the reverend 

 gentleman, but what does Hoyle say to this ? Mr. Foord, too, 

 would hardly agree that the fossil Nautiloidea are classified according 

 to his Catalogue, 1888-1891, for in his i8gi part he removed 

 Bactrites to the Ammonoidea. Of course, one regrets the retention of 

 the division into Dibranchiata and Tetrabranchiata ; Mr. Cooke 

 mentions the other views, but has a remarkably imperfect apprecia- 

 tion of the arguments on which they are based. There is a curious 

 slip on p. 14, where Dreissensia is said to be " closely allied to 

 Mytihts," although, in the systematic part, the two are referred to 

 distinct orders. The classification of the Pelecypoda is according to 

 Pelseneer and based mainly on the gill-characters. This is doubt- 

 less an improvement on the old method, though a palaeontologist may 

 regret that no mention should be made of Neumayr's suggestive 

 attempt. 



Some strange lapses in morphology are also hardly suitable for 

 the student, unless he be so advanced as to correct them for himself. 

 He will, however, be clever if he discovers what Mr. Cooke means by 

 saying that " the membranous siphuncle" of Spivnla "is connected with 

 the posterior part of the liver." The shell of Spirilla is not " of the 

 Tetrabranchiate type " ; for it is coiled in the reverse direction and 

 there are other differences. But all Mr. Cooke's remarks on the shell 

 of the dibranchiate Cephalopoda are difficult for a reviewer to 

 characterise. If, with the majority of English writers, he fails to 

 understand the not very obscure homologies of the Sepia shell,' one 

 does not willingly ascribe this to ignorance or obstinacy. Yet it cannot 

 be lack of intelligence, if only for the reason that so little is required. 

 We are told that the " arms " of the Dibranchiata are modifications 

 of the molluscan foot; but similar information is not vouchsafed 

 concerning those of Nautilus, which are uniformly spoken of as 

 " tentacles." On p. 445, under Scaphopoda, it is said, " there is no 

 special respiring apparatus, heart or arterial system, breathing being 



1 As maintained by Voltz, Gegenbaur, Lankesler. Steinmann, etc., etc. 



