378 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [34] 



biistus the upper lateral carina begins just back of the base of the eye- 

 stalk, and below and entirely separate from the posterior fading out of 

 the lateral carina of the rostrum ; is very sharp and prominent above the 

 broad, depressed, and concave antenno-hepatic region, which is separated 

 from the branchial region by an oblique branchio-hepatic carina, con- 

 necting the upper with the nearly straight, sharp, and prominent lower 

 lateral carina. The posterior part of the upper carina, back of the 

 branchio-hepatic, is less prominent than in front, nearly straight, and 

 diverges very rapidly from the lower carina, while in gihbosus these cunuse) 

 are figured as very nearly parallel. In rohv^tus there is a well-marked 

 submargiual carina nearly the whole length of the inferior margin. 

 Nearly the whole surface of the carapax between the carinse is marked 

 with minute dendriform elevations, which look somewhat like, but are 

 apparently not, minute wrinkles due to contraction; otherwise the 

 surface of both carapax and pleon is nearly smooth and quite naked. 

 The eyes are well developed, nearly hemispherical, somewhat swollen, 

 two-thirds as broad as the length of the eye and eye-stalk, conspicuously 

 faceted, black, and face somewhat obliquely inward. In the male the 

 proximal part of the ui)per flagellum of the antennula, for a distance 

 the length of the antennal scale, is compressed, broadly expanded, and 

 the outer inferior surface clothed with very short hairs ; while in the 

 female the same part is similarly but very much less expanded. 



The peraeopods, especially the three posterior pairs, are apparently 

 considerably stouter in rohustus than in gibbosus, and the ischia and 

 meri in the three posterior pairs are all armed with small spines along 

 the lower edge in robustus, while Milne-Edwards's figure shows no such 

 spines anywhere upon the posterior pair, and none upon the ischia in 

 the third and fourth pairs. In Milne-Edwards's figure, however, an 

 articulation is incorrectly introduced in the merus in the fourth and fifth 

 pairs and apparently also in the third, so these appendages are very 

 likely incorrectly figured in other respects. 



The dorsal carina of the pleon is apparently less conspicuous in ro- 

 bnstus than in gibbosus, and the teeth in which it projects at the third, 

 fourth, fifth, and sixth somites are much shorter. The dorsal facet of 

 the first somite is overhung behind by a sharp lamellar projection, be- 

 neath which the posterior margin of the carapax fits when the pleon is 

 extended, and which is continuous either side with the pleuron, which 

 broadly overlaps the side of the carapax. 



The entire integument of the animal is rather soft and membrana- 

 ceous, but in the specimen figured the form is very well preserved. Soon 

 after preservation in alcohol, and, according to the statement of Mr. 

 Benedict, before the color had changed materially from that of life, the 

 entire animal, except the eyes, was very intense dark crimson. 



The oral appendages are essentially as in Acanthephyra Agassizii^biiCi 

 the number and arrangement of the branchiae are the same as in that 

 species. 



