672 THE VOYAGE OF H.M.S. CHALLENGER. 



the frontal and gastric region, and produced to a long and slender rostrum which is armed 

 superiorly with thirteen movable spines interspersed with short hairs. Eostrum longer 

 than the carapace, smooth on the anterior half of the upper margin, directed slightly 

 upwards and armed on the lower surface with thirteen or fourteen rigid teeth interspersed 

 with short hairs. 



The pleon is smooth and polished ; the third somite is slightly compressed dorsally, 

 and slightly arcuate, the posterior margin being mesially produced posteriorly, and over- 

 lapping the fourth somite ; the sixth somite is nearly twice the length of the fifth. The 

 telson is long, narrow, dorsally flat and laterally compressed, each dorso-lateral surface 

 being longitudinally armed with seven small movable spines, of which the posterior stands 

 at the distal angle, while the extremity is furnished with three small spines and a few hairs. 



The ophthalmopocla (fig. 3«) are pyriform, in consequence of the smallness of the 

 stalk on which they stand. The ophthalmus is quite or nearly hemispherical, the posterior 

 margin of the pigment extending at one point to form a rudimentary ocellus. 



The first pair of antennas (fig. 3&) has the first joint deeply excavate for the reception 

 of the ophthalmopod, and carries on the outer side a stylocerite that is not at all style- 

 like, being a smooth, round disc, produced anteriorly. In this it resembles Pandalus 

 annidicornis and Pandalus falci<pcs. The second and third joints are cylindrical, 

 extending to nearly half the length of the rostrum, and distally supporting two 

 flagella, of which the outer is the larger and somewhat the longer, equalling in length 

 the entire animal. This character furnishes a ready diagnosis of this species from 

 Pandalus, the flagella of which do not reach beyond the extremity of the rostrum, and 

 are about the length of the carapace. 



The second pair of antennas offer nothing very remarkable excepting that the scapho- 

 cerite is long, being nearly the length of the carapace. The margins are subparallel, the 

 outer being rigid and terminating in a sharp tooth near the apex. 



The mandibles have the molar process long, with the grinding surface ovate ; the 

 psalistoma is narrow and bidentate. The first joint of the synaphipod is broader than 

 the two succeeding, which terminate in a rounded extremity. 



The oral appendages possess a strong resemblance to the typical species, as do also the 

 two pairs of gnathopoda, the second pair having no ecpbysis, which is present in its near 

 ally, Nothocaris. 



The first pair of pereiopoda (fig. 3&) is a little more slender than the second pair of 

 gnathopoda, and has the terminal joints less hirsute. It is remarkable also for the large 

 squamiform development of the ischial joint, the lower margin of which is fringed on the 

 inner side with a row of hairs. The second pair is like that in Pandalus annulicornis, 

 but more uniform in length and strength on each side. The three posterior pahs have 

 only one spine on the ischium and six on the meros, subequally distant, and three on 

 the carpos. 



