beonn's animal kingdom. 357 



so many eminent Zoologists, that tlie greater groups of the Mala- 

 cological system may now be regarded as generally agreed upon, and 

 we scarcely look for any alterations in them except from writers who 

 are urged by a restless spirit of innovation. That Professor Bronn 

 was rather conservative, perhaps almost too conservative, in his mode 

 of treating some zoological questions, is evident from what we have 

 already stated, and he shows a similar spirit in his primary classifica- 

 tion of the Mollusca. Instead of adopting Milne-Edwards' division of 

 this great sub-kingdom into Molluscoida and Mollusca proper, a course 

 which has received the approbation of most modern Zoologists, he 

 reverts to the old Cuvierian arrangement, and divides the group into 

 two sub-groups ; the Malncozoa acephala and the M. cepJialota or 

 Cephalo-malacia. Among the former, however, he again recognises two 

 groups to which he gives the names oi Saccacephala and Gonchacephala; 

 theformer including the Bryozoa andTumcata(Mo/ZMScoic?a),the latter 

 the ordinary Bivalves and Brachiopods. In the classification of the 

 Bryozoa (for which he retains Ehrenberg's name) the author follows 

 Professors Allman and Busk ; in that of the Tunicata he has adopted 

 a new system, or rather a remodelling of an old one, which does not 

 seem to us to be particularly happy. Neglecting the results of 

 Professor Huxley's investigations upon the affinities of these animals, 

 he divides the class Tunicata into two orders, Nectascidia and Chtho- 

 nascida, distinguished solely by the presence or absence of the power 

 of natation, by which means Pyrosoma and DoUohim are united with 

 the Salpce, although curiously enough, the former is parenthetically 

 stated to be " most nearly alHed to the Botryllina:' 



In the Brachiopoda {Brachionacephala, Bronn), the LingulidcBy 

 JDiscinidcE and Oraniadce are separated from the rest of the class to 

 form an order called Pleuropygia, in allusion to their possession of 

 an anus, and in opposition to the term Apygia applied to the other 

 forms in which no anus is present. These groups are further 

 characterised by the existence of a toothed hinge in the latter and its 

 absence in the former. The LameUibranchia are likewise divided 

 into two orders, the Sippuritidce heing separated, under the name of 

 Endocardinesy from the rest of the class ; to which the name of 

 Exocardines is given. 



In the arrangement of the Cephalophorous Mollusca here adopted 

 the Bentalia figure as a distinct class, for which the name of Frosopo- 

 cephala or ScapJtopoda is proposed. The Pteropoda, on the contrary, 

 are referred to the Gasteropoda, among which they apparently take 

 an ordinal rank. The other orders of Gasteropoda adopted are the 



