in the Amphipoda. 373 



maculatus ? is somewhat larger than the second, but is of the 

 same general shape ; the carpus bears numerous setse irregu- 

 larly arranged on the posterior margin ; on the anterior 

 margin there is only one tuft at the antero-distal angle ; the 

 propodos is supplied with many setaj arranged as in the second 

 gnathopod ; the palm is very oblique, slightly curved, and is 

 defined by a stout spine or seta, which is much more promi- 

 nent than the corresponding one in the second gnathopod. 

 The length of the palm varies considerably ; in a tracing of 

 a drawing made by Mr. Thomson, which he has sent me, the 

 palm is represented as occupying almost the whole of the 

 posterior margin of the propodos ; in the figure which I give 

 (PI. X. fig. 6), taken from a female bearing eggs, it is 

 scarcely more than half as long as the propodos ; it most 

 probably increases in length with the age of the animal. The 

 dactylos is stout and strongly curved, and is similar to that of 

 the second gnathopod. 



In Aora typica (see PL X. fig. 2) the coxa of the first 

 gnathopod is produced anteriorly into a sharp point, as in 

 Aora gracilis * j the basos is long and is produced into a 

 tooth on the anterior margin at a pomt not far from the base 

 of the joint ; there are a few very small setge at intervals 

 along the anterior margin ; at the distal end the integument 

 is produced anteriorly and distally, so as to form a thin plate, 

 which interlaps with a similar but larger plate arising from the 

 ischios. The meros is produced inferiorly into a long acute 

 spine, which is as long or very nearly as long as the carpus • 

 the carpus is longer than the propodos, sides parallel, posterior 

 with a few small tufts of setae near the distal end ; propodos. 

 slightly arcuate, with no distinguishable palm in full-grown 

 specimens ; the distal portion thickly covered with long hairs,, 

 arranged in short transverse rows and most numerous at the 

 base of the dactylos. Dactylos slightly curved, of nearly 

 the same width throughout until it narrows suddenly near the. 

 end. 



In smaller and presumably younger specimens there is a 

 stout seta about the centre of the inferior margin of the pro- 

 podos, marking off what may be considered a " palm ; " this 

 is entirely absent in large specimens (see PI. X. fig. 3) . In 

 these young males the first gnathopod is much more like 

 the first gnathopod of the female than in the full-grown males. 

 I have already described a case similar to this in Podocerus 

 longimanus j. 



* See Bate and Westwood, ' British Sessile-eyed Crustacea/ figure on 

 p. 281, vol. i. 

 t ' Transactions New-Zealand Institute,' xvi. p. 256. 



