72 Transactions. — Zoology. 



Genus Antlmra, Leach. 

 (Bate's and West-wood's Brit. Sessile-eyed Crust., vol. ii., p. 157.) 

 Antliura affinis, sp. nov. Plate I., fig 4. 



Segments of pereion subequal, cylindrical. Head somewhat shorter than 

 the first segment of pereion. Antenna? short, not quite so long as the head; 

 upper much smaller than the lower, consisting of four joints, of which the 

 basal one is the largest, and a very small fifth joint bearing a small pencil 

 of setae ; lower antennae thick and strong, basal joint large, broad, with a 

 groove above in which the upper antenna rests, the inner edge of this basal 

 joint is straight and in close contact with that of the antenna on other side, 

 along the median line ; basal joint followed by three subequal joints, and a 

 short, thick, rudimentary flagellum, the joints of which bear setae thickly 

 set on one side. 



First pair of legs very strong, not reaching beyond the head ; basos very 

 thick distally, ischios also thick and strong, meros short, carpus subtri- 

 angular, produced along the side of the propodos, and bearing setae on its 

 distal extremity ; propodos thick, ovate, in contact with both meros and 

 carpus, palm short with a strong projection against which the dactylos 

 impinges ; dactylos short, strong, and curved. Eemaining legs all similar, 

 not subchelate, propodos longer than the carpus and meros together. First 

 five segments of the pleon united so closely that the lines of suture cannot 

 be distinguished, sixth segment distinct bearing biramous appendages ; 

 outer ramus of a single joint, half as long as the inner, semicylindrical 

 surrounding the inner ramus, its upper iuner edge serrate and fringed with 

 long setae very delicately plumose ; inner ramus of two joints equal in 

 length and breadth, broad, edges fringed with long setae ; telson broad, 

 round at end, with several long setae near the centre. 



Colour — pale yellow with blotches of black on the head, segments of 

 pereion, pleon and telson. Length about ^ of an inch. 



Hab. Lyttelton Harbour. Found on seaweed at low tide. 



This species is a true Anthura, coming apparently near to A. gracilis, 

 from which however it is sufficiently distinct. 



The first pah' of legs only are chelate, all the rest are simple ; they 

 have the dactylos large and strong, the end forming a claw distinct from 

 the basal portion ; at the base of this claw three or four simple setae 

 arise laterally, and a short stout one on the inside. There is also a 

 short stout seta on the inner distal angle of the propodos (pi. I., fig. 4 c 

 and d). 



The pleopoda are of the usual form, having a short basal joint bearing 

 two equal oval plates with the distal margins setose. Each of these bran- 

 chial plates is slightly constricted on each side, half way between the two 



