P.EC1LASMA KjEMPFERI. 103 



rum acumine basali truncato, margini occludenti pcene 

 p ar allele- . 



Valves 5 ; carina with a truncated and crested base ; 

 scuta with strong internal umbonal teeth ; terga with 

 the basal point truncated, almost parallel to the occludent 

 margin. 



Maxillae with short thick spines in the notch under 

 the two upper great spines; caudal appendages with 

 scattered bristles on their summits, and along their whole 

 outer margins. 



Japan ; attached, in great numbers, to the upper and under sides of the 

 Inachus Kampferi of De Haan, a slow-moving brachyourous crab, probably 

 from deep water. British Museum. 



General Appearance. — Capitulum rather compressed, 

 narrow, and produced. Valves white, tinged with orange, 

 smooth, moderately thin, occasionally with faint traces 

 of striae radiating from the umbones. Scuta, apex pointed, 

 with a very slight ridge running to the umbo; basal 

 margin equalling two thirds of the length of the terga, 

 with an internal basal rim ; on the under side of each 

 valve, beneath the umbo, there is a strong tooth. Out 

 of the numerous specimens, all excepting one had then- 

 scuta unequally convex, with their occludent margins 

 unequally curved, that of the more convex valve at 

 the umbo, curling beyond the medial line. The basal 

 end of the carina is, likewise, slightly curved laterally, 

 and always turns towards the more convex valve. This 

 inequality, as Mr. Gray pointed out to me, depends on 

 the position of the specimens ; the flatter side lying close 

 to the carapace of the crab. Terga, flat, oblong, nearly 

 rectangular; occludent margin straight; basal angle, 

 truncated, almost parallel to the occludent margin ; in 

 width, three or four times as wide as the carina. Carina, 

 (fig. 1, a) short, narrow, slightly curved, upper part 

 broadest, with the apex rounded, only just passing up 

 between the basal broad ends of the terga ; externally 

 carinated, internally very slightly concave ; basal end 



