Eev. Canon A. M. Norman on British Mjsidae. 157 



Male. Peduncle of antennules with sexual appendage very 

 small, tubercular. First perajopods stronger than the rest ; 

 distal joints short, expanded, furnished with long strap-formed 

 appendages. Pleopods with largely developed peduncle, the 

 first consisting of a single branch, the rest with two multi- 

 articulate branches, and a subovate laminary plate at the 

 base of the inner branch ; outer branch of fourth pair about 

 three times as long as inner, multiarticulate (ten articula- 

 tions), terminating in not long spiniform setse. 



Anchialus agih's, G. (). Sars. 



1870. Anchialus agilk, G. 0. Sars, Middelhavets Mysider, p. 70, 



pis. xxvi.-xxviii. 

 1883. Anchialus agilis, Czerniavsky, /. c. fasc. iii. p. 42. 

 1885. Anchialus agilis, Carus, /. c. p. 468. 



This little species is of very robust form, the breadth both 

 of cephalothorax and pleon being greater in proportion to 

 their length than in any other European Mysidean, the 

 cephalothorax wider behind tlian in front. Rostrum some- 

 what linguiform, of considerable size, concealing the greater 

 part of tirst joint of antennules. Peduncle of antennules 

 stout, of moderate length, first and third joints subequal. 

 Antennal scale minute, scarcely reaching extremity of penul- 

 timate joint of peduncle of antenna, and not half as long as 

 peduncle of antennules, subrhomboidal, rather more tiian 

 twice as long as broad ; outer margin naked, terminating in 

 a spine, beyond which the apex is obliquely truncate, and is, 

 as well as inner margin, ciliated ; from the inner side of the 

 first joint of the antennaj there springs a long spine, which is 

 serrated on the edges. Legs having the fourth joint much 

 longer than the third, and the tarsus composed of three 

 articulations. Pleon having the epimera produced downwards 

 and backwards, angulated, and edged witli finely plumose 

 setaj. Telson very large, as long as the long inner uropods, 

 and half as long as the pleon, the margins straight, and 

 gi'adually and but slightly converging from the base to the 

 extremity, which is incised to a depth subequal to breadth of 

 same part of telson ; sides of telson with about thirty ciliated 

 spines, terminal spines much larger than the rest, the cleft 

 minutely and closely dentated. Uropods having the auditory 

 apparatus small ; inner uropods with inner margin edged 

 with ciliated spines of unequal length and fine hairs; apex 

 terminating in two spines of much larger size ; outer margin 

 edged with fine hairs. Outer uropod having inner margin 

 edged with fine hairs, and the outer bearing about thirty 

 simple subequal sj)iucs. Length 8 millim. 



