272 ZOOLOGY OF THE FAR EAST. 



apex of the telson is, in the same species, by no means constant. I have checked 

 Pesta' s observations by an examination of Irish specimens of P. varians and can in a 

 large measure substantiate his statements.'^ Consideration of the text- figures which 

 Pesta has given, affords convincing proof that Allocaris is nothing more than a 

 synonym of Palaemonetes and that Sollaud formed a completely erroneous estimate of 

 the value of the characters he discovered. On the other hand Pesta is undoubtedly 

 wrong in suggesting that the Chinese species is merely a local race of P. varians. 



More recently Sollaud has described another genus, Coutierella, based on a fresh- 

 water Palaemonid from South China, and this also must be relegated to the synonymy 

 of Palaemonetes. Coutierella is distinguished from Palaemonetes only by the form of 

 the second maxilla and first maxillipede, the latter bearing a very close resemblance to 

 the same appendage in Palaemonetes sinensis, while the former appears to differ from 

 that of all Palaemonids in which it has been examined in the absence of the re-entrant 

 angle in the margin below the two distal laciniae and in the presence of setae on this 

 margin. It is clear from Pesta' s work that the characters drawn from the first 

 maxillipede do not form a valid generic distinction, and even in the Palaemonidae, in 

 which genera are separated by such comparatively slight distinctions, the features of 

 the second maxilla cannot by themselves be held to have the importance that Sollaud 

 has ascribed to them. 



In describing Caridea a study of the mouth-parts is far too often neglected ; it is 

 much to be regretted, therefore, that Sollaud in his discovery of certain most interest- 

 ing points in the structure of these appendages in the Chinese species of Palaemonetes 

 has adopted such extreme views regarding their evolution and classification. 



Palaemonetes sinensis (Sollaud). 



1911. Allocaris sinensis, Sollaud, Bull. Mus. d'Hist. nat., p. 50, text-figs, i, 2. 



This species is certainly not a local race of P. varians as suggested by Pesta {lac cit.) . 

 It may be distinguished by the following characters : — 



(i) The teeth on the upper border of the rostrum extend nearer to the apex. 

 In P. varians the distal quarter of the rostrum is usually unarmed, whereas in 

 P. sinensis it bears a tooth. In P. sinensis the foremost tooth of the dorsal series is 

 situated above, or in advance of, the distal tooth on the lower border ; in P. varians 

 the foremost inferior tooth is in advance of all those on the upper edge. 



(ii) The two ultimate segments of the antennular peduncle are proportionately 

 shorter and the free portion of the accessory antennular ramus is nearly four times as 

 long as the fused basal part. In P. varians the fused portion is very much longer, 

 the free part of the accessory ramus being only about one third its length. 



(iii) The antennal scale is a little broader (about two and two third times as 

 long as wide) and is a trifle more broadly rounded distally. 



(iv) The coxa and basis of the first maxillipede are more widely separated. 



1 In a number of Irish specimens the form of the first maxillipede is intermediate between those shown in Pesta's 

 figs. 9 and 10 and in some it is almost as extreme aa in fig. 10. There are as a rule only two setae at the apex of the 

 talson, but in a few examples four were found. 



