MYSIDACEA— TATTERSALL. 295 



broad, ovate lanceolate in shape, setose all round, terminal joint distinct, a prominent 

 spine on the outer distal corner of the joint from which the scale springs. 



Antennular peduncle more slender in the female than in the male ; antennal 

 peduncle equal in length to the first two joints of the antennular peduncle. 



Tarsal joint of all the thoracic limbs composed of three joints, the first longer 

 than the last two combined, third slightly shorter than the second, dactyl us 

 rudimentary ; the thoracic limbs are long and slender and well provided with fine 

 setae. The outer corner of the basal joint of the exopod is rounded. 



Sixth abdominal somite twice as long as the fifth. 



Telson about three-quarters of the length of the sixth abdominal somite, two- 

 thirds of the length of the inner uropod and half the leng-th of the outer uropod, cleft 

 for about a quarter of its length, about one and a half times as long as broad as its base. 

 Cleft armed with a pair of plumose setae and with a regular series of teeth aboiit thirty 

 in number on each side. Lateral margins armed with about 12-14 spines arranged 

 more or less regularly, the proximal spines somewhat larger and stouter than the distal 

 ones, except the terminal spines which are about one-tenth of the length of the telson. 



Inner uropod one and a half times as long as the telson with a group of 15-20 

 closely set spines on the inner margin, commencing slightly distal to the statocyst, 

 and ending about one quarter of the length of the uropod from the apex. 



Outer uropod twice as long as the telson and one-third longer than the inner. 



Exopod of the fourth pleopod of the male longer than the endopod with a strong 

 modified seta on each of the antepenultimate and penultimate joints, terminal joint 

 small and furnished with two fine setae. 



Length of adults of both sexes, 9 mm. 



Remarks. — The male differs froin the female, in addition to the usual secondary 

 sexual characters, in having the eye rather shorter and stouter and in the stouter 

 form of the antennular peduncle. The anterior end of this species recalls somewhat 

 strongly that of the common Mesopodojms slabheri (v. Ben.) of European waters in 

 the form of the eyes, the roundly arched frontal plate, and the acute antero-lateral 

 angles of the carapace. It is distinguished from all other species of the genus by 

 the combination of these three characters in addition to the shape and armature 

 of the telson. 



17. Tenagomysis rohusta, sp. nov. (Plate IV, figs. 1-5.) 



Occurrence. — Station 135, north of New Zealand, one male, one female, two 

 immature. 



Description. — A small robust species in which the carapace leaves the last thoracic 

 somite exposed, antero-lateral corners of the carapace rounded, front margin of the 

 carapace produced into a very short obtusely pointed rostral plate. 



Eyes moderately large, cornea occupying about half of the whole eye, pigment 

 black, eyestalk minutely hispid on the anterior surface. 



