370 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
The antennae are widely separated and seem to be composed of 
three articles. The antennulae are concealed by the mazxillipeds. 
The tips of the mandibles project between the maxillipeds. 
The five pairs of legs are crowded closely together, within the oral 
area. There are five pairs of incubatory plates. The first and fifth 
pairs are the largest and overlap the other three pairs, so as to partly 
or entirely conceal them. By carefully lifting these the others are 
easily seen lying beneath. The pleopoda consist of a single pair of 
large plates situated on the ventral side of the body just below the 
last pair of incubatory plates. There are no uropoda. 
On the posterior margin of the border which surrounds the pleopoda 
at the terminal part of the body are eleven teeth, one in the median 
line, and five on either side. These teeth indicate the coalesced ab- 
dominal segments. 
Locality Only one specimen, a female was collected at Station 
4,621 in latitude 6° 36’ N., long. 81° 44’ W. at a depth of 581 fathoms. 
The host is unknown. 
Type.— Cat. No. 46,482, U.S. N. M. 
Only three other species of this genus have been described, Zono- 
phryxus retrodens Richardson, Z. trilobus Richardson, and Z. grimaldu 
Koehler. The present species is very close to Z. trilobus but differs 
in the narrower cephalic region, which is more triangular in appearance 
in both a dorsal view and a ventral view, in the presence of eye pits, 
in the invisibility of the cephalic border in a dorsal view, in the contour 
of the body, and in the greater number of teeth on the posterior border. 
COLYPURIDAE. 
CoLypurRuS AGASSIZI Richardson. 
Colypurus agassizi Richardson, Bull. M. C. Z., 1905, 46, p. 105-106. 
Body gradually increasing in width backward from the first to the 
fourth free thoracic segment. The head is 2 mm. wide, the first free 
thoracic segment is 3 mm. in width, and the fourth free segment meas- 
ures4mm. The length of the body is 5 mm. 
The head is produced in the middle anteriorly in a rounded lobe. 
The sides of the head are also expanded in rounded lobes. Four knob- 
like bodies are situated in a transverse series on the dorsal surface of the 
head, the two central ones being largest; the lateral knobs are placed 
one on each lateral lobe. The antennae are rudimentary, inconspicu- 
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