200 STALK-EYED CRUSTACEA 
HEMIPENEUS Bare. 
Ann. Mag. Nat. Hist., 5th Ser., VIII. 186, 1881; Rep. Challenger Macrura, p. 299, 1888 [Hemipeneus]. 
Hemipeneus spinidorsalis Bare. 
Plate L., Fig. 2. 
Ann. Mag. Nat. Hist., 5th Ser., VIII. 186, 1881; Rep. Challenger Macrura, p. 301, Plate XLIV. 
Fig. 1, 1888. 
Station 3374. 1823 fathoms. 3 males, 1 fem. 
ee ZaKeo.- 120i cs 1 fem. 
66 3398. 1573 € 2 males. 
33 3399. 1740 es 1 male, 2 fem. 
«= 3.400. 91322 e 1 male, 1 fem. 
o 3413. 1360 « 1 male. 
This species, the type of the genus Hemipeneus, was discovered by the 
naturalists of the “ Challenger” Expedition near Tristan d’Acunha in the 
South Atlantic, and near the Philippine Islands. Three specimens were 
captured, all at great depths (1,900 and 2,050 fathoms). Bate’s figure was 
drawn from a small specimen, 57 mm. in length. The differences apparent 
when one compares this figure with the much larger “ Albatross’ specimens 
may be plausibly attributed to the disparity of age and to errors of the 
draughtsman. The great length of the ischium joint of the chelipeds, a 
feature not mentioned in Bate’s description, nor seen in any other species of 
the genus, is doubtless due to an error in the drawing. In the “ Albatross” 
examples the median dorsal line of the carapace is distinctly convex and 
rises into a low carina which is continuous from the base of the rostrum to 
the posterior border of the carapace. The dorsal carina is apparent also on 
the posterior half of the third, fourth, and fifth abdominal segments, and, to 
a greater degree, through the whole length of the sixth abdominal segment. 
The eye-stalks are flattened horizontally, and furnished with a small tubercle 
on the middle of the internal margin. The flagellum of the second antenna 
is enormously long, much more than twice the length of the body. The meri 
of the chelipeds are compressed. 
The rostrum of the adult male varies in length from one third to nearly 
one half the length of the remaining portion of the carapace. It is always 
much shorter than the antennular peduncle. In the adult female, on the 
contrary, the rostrum is much longer than the antennular peduncle, varying 
