56 CRUSTACEA MALACOSTRACA. III. 



Remarks. Though the specimen described and figured is extremely mutilated, I think that 

 the species is sufficiently characterized by the small processes on third and fourth segments and the 

 shape of abdomen. 



Occurrence. Taken by the "Ingolf" at a single station. 



Davis Strait: Stat. 24: Lat. 63°o6' N., Long. 56°oo' W., 1199 fath., temp. 24 ; 1 mutilated spec. 



HeterOmeSUS Richardson. 



Body moderately slender or proportionately robust. Antennulse with the part beyond second 

 joint considerably or extremely reduced, consisting of three or two very or extremely short joints. 

 Antennse with third joint elongate, more than two and a half times as long as the fourth and even 

 longer than the fifth or the sixth. Maxillipeds (PI. VI, fig. 4 o) with second joint extremely large, and 

 its lobe more than half as broad as the joint and much shorter than broad; the joint itself is con- 

 spicuously more than half as long again as the distinctly 5-jointed palp; second and third joints of 

 the palp very small, the second slightly broader than long. — The articulation between fifth and sixth 

 thoracic segment distinct, movable, while the two posterior segments and abdomen are immovably 

 fused. First pair of thoracic legs (PI. V, fig. 6d; PI. VI, fig. 4 p) with fifth joint much expanded, con- 

 siderably deeper than the fourth, broadest considerably beyond the middle, with a long, strong spine 

 a little before the distal end of the lower margin, and a similar spine at the lower angle of the long, 

 oblique terminal margin. — Uropods one-jointed. 



Remarks. The animals belonging to this genus are generally more robust than those of the 

 preceding genera. They are greyish or brownish, frequently even somewhat dark. The species are 

 evidently numerous, and some of them so closely allied that a careful investigation is necessary in 

 order to separate them and make them recognizable. 



Five species have been established, viz. two "Challenger" species by Beddard, one species by 

 Tattersall, and two species by Harriet Richardson. Our material contains four species, all new. 



41. Heteromesus dentatus n. sp. 

 (PI. V, figs. 6 a— 6 d; PI. VI, figs. 1 a-i c). 



Female. The material comprises the four anterior thoracic segments with head and appendages 

 of a specimen with the marsupium rudimentary, and, besides, a much younger specimen. 



Body moderately slender, densely set with minute, sharp granules, some among them a little 

 larger, spiniform. — Antennulse about as long as the head (fig. 6 b); second joint about as long as the 

 interval between the antennulse, and almost four and half times as long as the remaining distal portion, 

 which consists of three joints (fig. 6 c), the two proximal oblong and slender, the third joint an exceedingly 

 small nodule. — Antennse (fig. 6 b) almost twice as long as the sum of the four anterior thoracic seg- 

 ments with head; third joint slightly shorter than the breadth of first thoracic segment, and this joint 

 has above near the distal end a conspicuous, oblong process directed upwards and forwards and ter- 

 minating in a minute spine, and below, somewhat from the base of the joint, another somewhat longer, 



