REPORT ON THE SOHIZOPODA. 



Terminology. 



Concerning the terminology, I have deemed it advisable in the present Report to 

 make use of that best known and most generally adopted by the carcinologists of the 

 present time, though I am well aware that the usual terms have not in all cases a 

 clearly defined scientific character. The manifold modifications, both in structure and 

 functions, affecting almost every part of the body in this extensive class of Arthro- 

 poda, must, in my opinion, make it very difficult, if not quite impossible, to establish 

 any nomenclature, that at the same time would give fully adequate terms for the several 

 parts, and also be equally applicable to all forms of the class. 



The attempts made with this object in view by certain eminent carcinologists, and 

 most recently by Mr. C. Spence Bate, do not seem to have been generally accepted by 

 specialists in this department, notwithstanding the great skill and inventive aptitude 

 shown in constructing the new terms sugfo-ested. 



In a strict sense, I think that one of the claims to attention presented by so decidedly 

 new a terminology would be its unquestionable applicabilit}^ not only to all forms 

 of Crustacea, but also, as invariably has been attempted with the older one, to its 

 embracing the other classes comprised in the vast subkingdom of the Arthropoda 

 (Pycnogonida, Arachnoida, Myriapoda, Insecta). This, however, would appear to have 

 been far from the object of the above carcinologists. For not only have they restricted 

 their investigations to the class of Crustacea, but it w^ould also appear that the several 

 new terms have been, in every sense, specially devised for some limited group of this 

 class, generally one of the higher ones (Decapods, Amphipods). It is obvious, therefore, 

 that many of the terms, constructed according to such a method, will not apply even to 

 aU the Crustacea, let alone to the other Arthropoda. 



Indeed, if any attempt be made to construct a new and more generally applicable 

 nomenclature, it seems imperatively necessary that the terms should be relatively 

 indefinite, and, as a rule, not involving the designation of any specific physiological 

 function, but merely structural characters in a more general sense. Only ■\\4thin limited 

 groups would, perhaps to a certain extent, more definite designations be applicable, but 

 even then merely as strict specific terms. 



It is obvious that several of the new terms j^roposed by Mr. Spence Bate are 

 of a strictly specific character, e.ij., pereion, pleon, gnathopoda, pereiopoda, pleo- 

 poda, and these terms therefore cannot, in my opinion, lay any claim to serve as 

 generally applicable designations for all the Crustacea, although they are extremely 

 significant and sufficiently adequate for some of the higher gi-oups. Thus any 

 carcinologist engaged in studying the very extensive order of Copepoda would, I feel 

 convinced, hardly adopt the terms " pereion " and " pleon " in the same sense as that 

 proposed \)j Spence Bate ; for in those animals the middle section of the body {" pereion " 



