ACANTHEPHYRA CRISTATA. 163 
carina, which becomes obsolete just before it reaches the posterior margin of 
the carapace; this crest is ornamented with seven teeth, and the anterior 
part of the rostrum bears four more teeth on its upper margin; the lower 
margin of the rostrum is armed with three or four teeth. The wall of the 
orbit is entire, the lower margin being continuous with the antennal spine 
by suppression of the normal infra-orbital angle. A sinuous carina runs 
from the antennal spine backward to the hind margin of the carapace, form- 
ing the inferior boundary of the gastric and cardiac areas. Below the 
branchiostegal spine a second lateral carina runs backward, and becomes 
submarginal on the posterior border of the branchiostegite. The first and 
second segments of the abdomen are destitute of a dorsal carina; the third 
and fourth are carinated, and armed with a posterior tooth, largest on the 
third segment; the fifth and sixth segments are rounded dorsally, and the 
fifth is furnished with a minute posterior dorsal median spine ; the posterior 
lateral margin of the tergum of the fourth and fifth segments is armed with 
a minute denticle just above the point of articulation with the next segment. 
In one specimen the telson is armed with about six pairs of minute dorsal 
spines, which are obsolete in the other specimen. In both, the posterior 
half of the lateral margins of the telson is spinulose; the apex of the telson 
is imperfect in both the specimens examined. The eye is large, black, and 
set obliquely on its peduncle; the inner margin of the peduncle is furnished 
with a rather long, blunt process, or tubercle. The antennal scales are about 
equal in length to the rostrum; they are armed with an external apical 
tooth, and are serrate on their inner margin. 
Length, 78 mm.; rostrum, 13 mm.; carapace, including rostrum, 27.5 
mm.; antennal scale, 12 mm. 
Station 3361. 1471 fathoms. 1 specimen. 
ce sasle lii2 ec 
This species, like A. debilis A. M. Edw. (=A. gracilis Smith) and Systel- 
laspis lanceocaudata Bate, has no carina on the dorsal surface of the fifth and 
sixth abdominal segments, and the orbit is continuous below with the an- 
tennal spine. On these characters, taken in connection with the large size 
and small number of the eggs, Spence Bate established the genus Systel- 
laspis.* A genus founded on a physiological peculiarity combined with such 
trivial structural characters can hardly be accepted asa valid one. A. evis- 
tata differs from A. debil’s in having a much shorter and fewer-spined rostrum, 
* Rep. Challenger Macrura, p. 757, 1888. 
