HALIPORUS NEREUS. 189 
from Peneopsis, although it is said to have but one arthrobranchia on the 
eighth (second maxillipedal) somite. Xiphopencus Smith * is distinguished 
from Peneopsis by the long styliform posterior legs, the absence of gills on 
the posterior thoracic somite, ete. 
HALIPORUS Barz. 
Ann. Mag. Nat. Hist., 5th Ser., VIII. 185, 1881; Rep. Challenger Macrura, p. 284, 1888. 
Haliporus nereus Fax. 
Plate XLVI, Fig. 1-1. 
Bul. Mus. Comp. Zoél., XXTV. 213, 1893. 
Integument membranaceous. Carapace lightly granulated. Rostrum 
about one third the length of the rest of the carapace, horizontal, armed 
with six teeth above (the hindmost one situated a little back of the orbit), 
ciliated below. Median dorsal line of carapace carinate, with two teeth on 
the posterior half of the gastric region. The sides of the carapace are armed 
with spines as follows: two on the antero-lateral margin, one of which is at 
the lower angle of the orbit (spina antennalis of Stimpson), the other over 
against the second antenna, at the anterior end of the cervical groove (spina 
branchiostegiana) ; a third spine (spina hepatica) les on the hepatic region, 
behind the antennal spine; a fourth is behind and on the same level with 
the branchiostegal spine ; a fifth still further back and on nearly the same 
level, on the hind edge of the cervical groove. The cervical groove is deeply 
impressed, and the orbital region is definitely bounded by an hepatic and 
a gastro-hepatic sulcus. The hindmost of the lateral spines of the carapace 
lies in the anterior angle of a triangular field enclosed by branches of the 
cervical groove. From the infero-posterior angle of this triangle two carinz 
run backward along the branchial area; the upper one ends at the postero- 
lateral margin of the carapace, the lower one meets the inferior sub-marginal 
carina of the branchial area before attaining the posterior border of the 
carapace. These two carine, with the submarginal ridge of the carapace, 
enclose a long oval area, which forms a conspicuous figure on the branchial 
regions. The third to the sixth abdominal segments are carinated, their 
pleurse broad and rounded. On the sixth segment the carina terminates in 
a small, acute, horizontal tooth. The sixth segment is twice as long as the 
* Trans. Conn. Acad. of Arts and Sci., IT. 27, 1869. 
