HANSEN: THE ISOPODA. 123 
more or less distinctly separated. Pleural plates not developed. The pleopods 
quite soft, of medium size, decreasing conspicuously in size from before back- 
ward and attached to the lateral margin ; each pleopod consists of a short 
peduncle and two lamellar oblong rami; the outer ramus much larger than 
the inner one. The uropods biramous ; the outer ramus a little smaller than 
the outer of the fifth pleopod, the inner ramus very short, almost rudimentary. 
The pleopods are curled to such a degree that it would have been impossible 
without much construction to draw a sketch of the abdomen. 
b. Male. 
The body is a little more than three times longer than broad, and from the 
fourth thoracic segment it decreases in breadth towards both ends (Fig. 2). 
Head. The dorsal surface rather convex ; the median portion of the anterior 
margin almost straight. No eyes. The frontal border bent slightly downwards 
(Fig. 2a). The antennula rather short, 3-jointed; the basal joint tolerably 
thick, and partly overlapped by the rostrum; the second joint slender and 
rather short, the third very small. The antenne comparatively long, 7-jointed ; 
the four proximal joints of about the same length, but decreasing much in 
breadth from the rather thick basal joint to the fourth one ; the fifth joint is 
short and very slender, the two last joints exceedingly small. The mouth 
forms a rostrum which, when seen from below, is triangular, considerably de- 
pressed and directed forward, reaching almost to the frontal margin of the 
head. The hypopharynx is very large, and just outside it is seen the very 
oblong lateral part of the labrum (d), the median part of which is concealed 
by the hypopharynx; at first I believed that these oblong organs were the 
mandibles, but a closer examination gave the result mentioned, while the man- 
dibles, being needles with brown apex, were discovered within the rostrum. 
Maxillule are not observed; the maxillee (f) are small semicircular lobes lying 
considerably behind the posterior edge of the labrum, The maxillipeds (g) 
are short, extremely slender, almost styliform. 
Thorax. The segments are rather convex, the incisions between them com- 
paratively broad and very deep ; the lateral margins are much curved when 
seen from the side. The legs increase considerably in length, and very much 
in thickness, from the first (Fig. 2 6) to the fifth pair (Fig. 2c) which is robust, 
with the hand very large; the two posterior pairs again decrease somewhat in 
size. The terminal margin of the hand is deeply concave, thus differing con- 
siderably from the preceding forms. | 
Abdomen. It occupies scarcely one fourth of the length of the animal; it is 
narrower than the last thoracic segment, shortly ovate in outline, without the 
slightest rudiment of segmentation or abdominal feet; both the ventral and 
especially the dorsal surface are very convex. 
Size. Uncommonly large, being 7 mm. long, and 2.3 mm. broad. 
Habitat. The branchial cavity of Glyphocrangon spinulosa Fax., from Station 
3424 (Lat. 21° 15’ N., Long. 106° 23’ W.), 676 fathoms, 1 female with its 
male. 
