66 THE VOYAGE OF If.M.S. CHALLENGER. 



the iipjier side of the pseudoi'ostiiil projcctiuii ; visual elements imperfectly developed. 

 Exposed 2)arl of trunk very slioj-t, though comj)osed of five well-defined segments. 

 Segments of tail keeled laterall}'. Antennae in male attaining the length of the bod}'. 

 Fii'.st jxiir of legs eomparatively short, not projecting in front of caraj)ace ; second pair 

 rather stout, with terminal joint very elongate and linear ; the three posterior pairs of 

 legs succe.ssively decreasing in length and only sparingly supplied with bristles. Inner 

 branch of uroj)oda, considerably larger than outer, with inner edge spinous. 



Remarl-s. — The species of tlie present genus are easily known by the exceedingly 

 large and vaulted carapace, which in most of the species exhibits a very marked sculpture, 

 pai'tly in the form of keels and partly as variously shaped protuberances. As to the 

 liml)s, the comparatively small size of the first pair of legs also furnishes a marked 

 and characteristic feature. No less than ten species belonging to this genus have been 

 described, seven of which occur otl' the Norwegian coast, two in the Mediterranean, and 

 one in the West Indian Archipelago. Two new species are now added from the 

 Challenger Expedition. 



14. Campylasiyis 'pacifica, n. sp. (PI. X. fig. G). 



Specific Characters. — ?. Carapace enormously developed, occupying more than 

 half the length of the body, and being produced posteriorly so as to arch over the 

 exposed part of the trunk ; dorsal surface boldly vaulted; anterior part only slightly 

 produced ; pseudorostral projection very short ; subrostral notch rather shallow. Sur- 

 focc of carapace without any keels or protuberances, but slightly uneven dorsally. 

 Ocular lobe rather broad, containing a whitish eye-pigment. Penultimate caudal seg- 

 ment entire, not subdivided. Uropoda very elongate, attaining the length of the four 

 posterior caudal segments taken together, branches scarcely half as long as scape. 

 Length, about 3 mm. 



Remarks. — The present species seems to be most nearly related to the Mediterranean 

 form, Campylaspis glabra, G. 0. Sars, from which it however dift'ers by the somewhat 

 more slender form of the body, by the carapace being slightly uneven dorsally, by the 

 shorter pseudorostral projection, and by the presence of a distinct, though rather shallow 

 sul)rostral notch. 



Description. — I have only had an opportunity of examining a single female 

 specimen of this form. The specimen, which had been mounted in Canada balsam, is 

 fairly well preserved, and measures in length about 3 mm. 



The form of the body (see PI. X. fig. 6) is comparatively somewhat more slender 

 than in most of the other species, with the anterior division greatly dilated and some- 

 what longer than the posterior, if the uropoda are excepted. 



The carapace is of quite a prodigious size, occupying more than half the length of 



