2 C. BOVALLIUS. REMARKS ON THE GENUS CYSTEOSOMA. 
as long as the following joints together, linear, serrated along 
both margins; the genu is very short, the tibia a little longer, the 
carpus stout, hairy, with a broad finely serrated process, a little 
shorter than the metacarpus. The metacarpus is linear, smouth 
on the outer, finely serrated on the inner margin. The dacty- 
lus is very short, scarcely a fourth of the length of the meta- 
carpus. The second pair (Fig. 8) are longer than the first, but 
of the same shape. The carpus is longer and narrower, pro- 
vided with small bundles of hairs along the smooth posterior 
and anterior margins, finely serrated along the inner side of 
the carpal process. The metacarpus is longer, serrated along 
the inner margin. The dactylusis as long as a fouttit of the length 
of the metacarpus. The third and fourth pairs are serrated along | 
the hinder margins of the four first joints, the fifth joint or meta- 
carpus, smooth at the posterior margin, carries $—10 bundles of 
fine hairs along the anterior margin, the dactylus is slender, termi- 
nal (Fig. 9). "The fifth pair of pereiopoda have the femur broad 
and long, five times longer than broad, serrated on both margins, 
the lower, anterior corner produced into an obtuse angle, the genu 
short, with the lower, anterior corner sharp; the tibia elongate- 
ovate, serrated along the anterior margin. The carpus and meta- 
carpus are long, smooth on both margins, the metacarpus longer 
than the carpus (22: 15), curved; the dactylus short, slender, sub- 
terminal (Fig. 10 and 11). The sixth pair are of the same buil- 
ding as the fifth, but shorter (3: 4), the lower, anterior corner 
of the femur sharper, the anterior margin of the carpus minu- 
tely serrated, the metacarpus nearly straight. The seventh 
pair are half as long as the fifth, the ferivt broader at 
the upper end, Herrated along both margins, the follo- 
wing joints smooth, the carpus carrying a bundle of long 
hairs at the lower, hinder corner. The metacarpus is twice 
longer than the carpus, broader at the lower end, and exca- 
vated at the tip, forming with the dactylus a kind of pincers. 
Along the anterior margin there are five bundles of hairs. (Fig. 
12). The dactylus is long, feebly curved. Branchial sacks are 
fixed at the bases of the fourth, fifth, and sixth pairs. 
The pleon and urus together are shorter than the five first 
pereional segments. 'The first pleonal segment is the longest, 
but scarcely longer than the last pereional one. 
The pleopoda (Fig. 13) consist of a long rounded peduncle 
and two thick and stout fagella, as long as the peduncle; the 
