ItEPOUT ON THE .SCHIZOPODA. 5 



the oarlier method, in jiduptiiig for tlic several sections of the liody, as well as for 

 the respective limbs, designations more indefinite in cliaraeter, and consequently 

 applicable on a wider scale. 



The terms most usually adopted for the two posterior sections of the body, viz., the 

 "thorax" and " abdomen," are certainly in this respect preferable to tlie much more 

 specific designations "pereion" and "pleon" proposed by Mr. Spencc Bate. But as 

 the sections so termed fur tlie Crustacea do not correspond with thos(_- for Insects and 

 other Arthropods, I have thought it better to select some other known designations of a 

 similar indefinite kind. The terms "trunk" and " tail" seem to answer the purpose 

 sufficiently well, and b(jtli have, too, been adopted by some carcinologists. 



Concerning the several limbs, I do not regard it necessary to change the well known 

 and familiar terms " antennte, mandibles, maxillae," which have, moreover, to a great 

 extent, been adopted for other Arthropods. I have likewise seen fit to retain for the 

 pair of limbs immediately succeeding the maxillae, the usual term " maxillipeds," more 

 especially since these limbs, as shown by Milne-Edwards, are found to belong to the 

 foremost section of the body, and thus in every case, even should their structure 

 be peculiarly modified, stand in more or less close relation to the oral parts. For all 

 the limbs belonging to the succeeding or middle section, the indefinite term " limbs of 

 the trunk" or "legs" may, in a more general sense, be applied, and only in the case of 

 peculiar structural differences, the more specific terms "gnathopoda, chelipeds, fossorial 

 legs, perciopoda, whirling legs, natatory legs, prehensile legs," &c., are to be substituted. 

 As regards the limbs belonging to the posterior section of the body (tail), for the same 

 reason, the general designation " caudal limbs " may be adopted, and only in particular 

 cases the specific terms " pleopoda, setiferous laniella3, caudal stylets, opercular and 

 branchial lamellae," &c. The hindmost pair of caudal limbs, dift'ering in most cases 

 essentially from tlie preceding, may perhaps be termed, in accordance with the proposal 

 of Mr. Spence Bate, "uropoda." Together with the last caudal segment (telson) these 

 limbs form in the liio;her Crustacea the so-called " caudal fan." 



To facilitate comprehension of the terminology made use of in the present Report, 

 the most essential terms are given below. A more detailed explanation woixld, I think, 

 be quite superfluous. 



Adult animal (female, male). 



Young animal. Larva (Nauplius-, Zoea-, Mysis-stage). 

 Pupa (in Lophogastridee and Mysidae). 



A. Anterior division of body (cephalon and trunk). Free segments of trunk. 



Carapace. — Rostrum (frontal plate) ; cervical sulcus ; lateral wings of carapace ; 

 dorsal area; regions ; dorsal spine; supra-orbital, antcnnal, and l)ranchio- 

 .stegal spines. 



