Sessile-eyed Crustaceans. 327 



The triturating organs of the stomach are fringed each with 

 thirty spines. 



The branchial vesicles are narrow and twisted. All the 

 ]ier£eopods are strongly spined. The first ])air are con- 

 siderably longer than the second and third, and considerably 

 shorter than the fourth and fifth. The side-plates of the 

 first and second are large and rliomboidal, of the tliird and 

 fourth broad and bilobed, those of the fifth being semioval. 

 In the first and second pairs tlie first joint is nearly parallel- 

 sided ; in the other three pairs it is oval, most reguhirly so in 

 the fourth, being in the third much smaller and ahnost 

 circular and in the fifth rather wider and a little more squared 

 than in the fourth. In the first, fourth, and fifth pairs the 

 finger has the ituier margin nearly straight. In the second 

 pair the finger is very short, abruptly narrowed on the irmer 

 margin halfway towards the nail ; in the third pair it is 

 equally short, rather stouter, with the inner margin less 

 abruptly narrowed and the outer minutely furred. In all the 

 pairs there is a setule near the base of the little nail on the 

 inner margin, and on the outer a pair of microscopic processes 

 of oval form. 



The pleopods have long membranaceous peduncles, carrying 

 two or three rows of small spines. The two coupling-spines 

 are very short, single-toothed. The rami have fifteen or six- 

 teen joints. 



The first uropods have the peduncles longer than the 

 slightly unequal strongly spined rami ; tlie second have 

 shorter peduncles, but slightly longer ihan the rami, of which 

 the inner is a little the shorter. In the third pair the single 

 ramus is much narrower, but not shorter than the peduncle. 



The telson is broadest near the base, narrowest at tlie trun- 

 cate end, on either side of wliicli is a small group of spinules, 

 another group being placed near the middle of the convex 

 lateral margins. 



The length of a good-sized male^ not including the antennai, 

 is four fifths of an inch. 



The colour is a very distinguishing character while the 

 animal is alive. The ground-colour is yellowish white, here 

 and there barred with deeper yellow, bordered along the side- 

 plates and across the head with a beautiful purple, bands of 

 which also sometimes extend across the back of the pleon. 

 The appendages of the perajon and pleon and the telson are 

 for the most part pellucid. 



The specific name is chosen to mark the discovery of a 

 representative of a genus now for the first time included in 

 the fauna of Great Britain. 



