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



border has an obscure double outline. The cervical grooves are but slightly indicated 

 and they unite in front of the cardiac area. The gastric area possesses two faintly 

 curved transverse ridges situated behind a point opposite the posterior border of the 

 eye-stalks, and separated by a shallow median groove which is continued forwards on 

 the frontal lobe ; the surface gradually slopes downwards in front of these ridges. The 

 branchial area bears a faint transverse V-shaped marking as in the last species. The 

 ocular peduncles are short and stout, with the corneas deeply pigmented. The first free 

 joint of the antennal peduncle bears a small acute tooth on its upper surface, the 

 penultimate joint is not twice the length of the ultimate ; the flagellum is more than 

 twice the length of the carapace. The pterygostomial area is separated from the carapace 

 by a well-marked fissure, its surface projects somewhat and bears a series of elevated lines 

 with a slight granular concavity above. 



The external maxillipedes have the ischium broadly rounded on the inner margin, 

 with its outer surface as well as that of the merus traversed by faint wavy lines ; the 

 merus has a conical subacute lobe projecting from its inner margin. 



The chelipedes are of large size and finely granular, with the carpus distinctly 

 serrated on both margins. The merus has its inner and distal margin produced into an 

 obtuse tooth, a few minute tubercles are present on the outer surface, and an acute 

 spinule occurs on the distal and inferior margin ; the carpus is armed with five or sis 

 pointed teeth on its internal border, the proximal four of which are separated from 

 one another by distinct fissures, the external border is slightly raised and bears about six 

 pointed teeth of small size, the lower surface is smooth and polished, with a deep 

 concavity along the inner margin ; the propodus when folded has its articulation with the 

 dactylus situated opposite the proximal end of the carpus, the upper surface is convex, 

 with a decided slope towards the outer border which is also convex and moderately sharp, 

 a few hairs and minute tubercles are present on the proximal half of the margin, while the 

 lower surface is glabrous and comparatively free from granules; the dactylus is considerably 

 twisted, and almost equal in length to the hand, the inner portion is distinctly raised ; the 

 fingers of the right chelipede are in contact, while a tolerably large hiatus exists between 

 those of the left side and their opposed margins are devoid of teeth. The ambulatory 

 limbs are slightly pubescent, a few minute spinules are present on the anterior borders 

 of the meral joints, and in the first two pairs of legs one or two also on the posterior 

 border near the distal end ; the dactyli terminate in a black horny claw, and each bears 

 three horny spinules on its posterior margin. 



The abdominal segments are smooth and polished externally. 



Breadth of carapace of a male 8 '8 mm., length of carapace 9 "5 mm., of extended 

 abdomen 8 mm., of chelipede 27 mm., of second ambulatory leg 18 mm. 



I have had considerable hesitation in separating this species from Petrolisihes similis, 

 Stimpson, with which it is closely allied ; possibly the examination of a larger series of 



