DECAPODS 97 
Owen, the rostrum is longer and narrower than in .S. afinis, extending to 
the extremity of the superior antennze; the dental formula was the 
same, 4°, in the 3 specimens preserved. According to Owen’s figure, 
the antennular peduncle extends about to the middle of the rostrum, the 
second and third segments are subequal, the thickened portion of the 
outer flagellum is shorter than the peduncle. The rostrum curves strongly 
upward in its anterior half. 
SPIRONTOCARIS BIUNGUIS Rathbun. 
Spirontocaris biunguis RATHBUN, Proc. U. S. Nat. Mus., XXIV, 899, 1902. 
This species of the gaimardii group is an inhabitant of deeper water, 
and is distinguished by its larger eyes, longer rostrum, subchelate dactyli, 
and by having an exopod and an epipod on the outer maxilliped, while 
the pereiopods are destitute of epipods. 
Carapace carinated on its anterior half or two thirds. Rostrum from one 
and a fourth to one and two thirds times as long as remainder of cara- 
pace, its poste- 
rior half or third 
gradually as- ee ee 
cending, the re- ~< - 
mainder more See 
abruptly $0; WD- _mesemeersSS=EOER) A 
per limb narrow, = aa 
the widest point eee 
in. front of the Fic. 44. Sfpirontocaris biunguis. Station 3324. @. Side. 
eyes lower limb 3 ciyits of ous of age 3 pairs oflege (Xm), 
a little wider than 
the upper; terminal third a slender sharp spine, not limbed ; 
dorsal spines 5 to 7 (two on carapace), ventral spines 4 to 7. 
Antennal spine strong; pterygostomian spine or tooth very small. 
Eyes very large and oblique, pyriform, the cornea covering the greater 
part of the peduncle. Antennular peduncle extending a little past the 
middle of the antennal scale; second joint three times as long as third; 
outer scale reaching to end of first segment; thickened portion of outer 
flagellum extending in the female one third, in the male two thirds of its 
length beyond antennal scale. This last is four fifths as long as carapace ; 
antennal peduncle reaching end of second segment of antennular 
peduncle; flagellum longer than the body. 
The tips of the maxillipeds are half way between the antennal peduncle 
and the tip of the scale. The first pair of feet attain the middle of the 
last joint of the antennal peduncle; the palm is less than twice as long as 






