182 THE ATLANTIC. (CHAP. III. 
The abdomen, which consists, as usual, of seven segments, has 
the central series of spines of the cephalo-thorax continued 
along the middle line. The sixth segment bears the caudal ap- 
pendages, and in the seventh, the telson, we find the excretory 
opening. The lateral borders of the body, and all the append- 
ages, with the exception of the first pair of ambulatory legs, are 
edged with a close and very beautiful fringe of hair of a pale- 
yellow color. 
There are two pairs (the normal number) of antennee, one 
pair of mandibles, two pairs of maxillee, three pairs of maxilli- 
peds, five pairs of ambulatory legs, and five pairs of swimmer- 
ets. As most of the appendages differ from those usually met 
with in the Astacidze only in detail, it is only necessary to men- 
tion that the interior antenne have two flagella, one of which 
is very long, longer than the external flagellum of the external 
pair. 
The form of the first pair of ambulatory legs is singularly 
elegant. They are 155 mm. in length—considerably longer 
than the body ; they are very slender, and end in a pair of very 
slender denticulated chele, with a close, velvet-like line of 
hairs along their inner edges. The rest of the ambulatory legs 
are much shorter, and all bear chele. The specimen captured 
being a male, the first pair of swimmerets are somewhat modi- 
fied. The four other pairs of swimmerets, which are 383 mm. 
in length, bear each two narrow swimming processes richly 
fringed with hair, and a short flagellum. 
The absence of eyes in many deep-sea animals and their full 
development in others are very remarkable. I have mentioned 
(“ The Depths of the Sea,” p. 176) the case of one of the stalk- 
eyed crustaceans, Hthusa granulata, in which well-developed 
eyes are present in examples from shallow water. In deeper 
water, from 110 to 370 fathoms, eye-stalks are present, but the 
animal is apparently blind, the eyes being replaced by rounded 
calcareous terminations to the stalks; in examples from 500 to 
