n>2 THE VOYACiE OF H.M.S. CHALLENGER. 



comparatively short ami thick, with the last joint liy far the largest. The male appendage 

 also exhibits a very similar aspect. 



The aiitennal scale (see fig. 17), on the other hand, looks very dissimilar, resembling 

 rather that occurring in the species of the genus Mysidopsis. It is about twice as long 

 as the antennular peduncle, and exhibits a very narrow, lanceolate form, with both 

 margins apparently fringed with setse in their whole length. On closer examination, 

 however, a dentiform projection is seen issuing from the outer edge, at a very short 

 distance from the base, and the part of the edge behind this projection does not exhibit 

 any seta3. Thus, the scale is, in reality, formed upon the same type as that in the other 

 species of the present genus, but is truncate obliquely to such an extreme degree, that 

 the inner linguiform-produced corner occupies well nigh the whole length of the scale, 

 whereas the outer corner has withdrawn to very near the base. The basal part of the 

 ilagellum is somewhat more produced than in the preceding species, being not much 

 shorter than the scale, and has the last joint the longest. The terminal part of both 

 this flagellum and those of the antennulas had been broken off near their bases. 



Habitat. — The above-described fragment I found in a bottle containing several larvte 

 of Decapoda and other Crustacea, taken off the entrance to Port Philip, Bass Strait. 

 The locality is given below, as follows : — 



Station 161, April I, 1874 ; lat. 38° 22' S., long. 144° 36' E.; depth, 33 fathoms; 

 sand. 



Genus 5. Anchialus, Kroyer, 1861. 

 Anchialm, Kroyer, Nat. Hist. Tidsskr., 2''''" R^kke, Bd. i. 



GeneHc Characters. — Form of body somewhat different in the different species. 

 Carapace more or less developed, with frontal margin produced in the middle. First 

 caudal segment in female with small horizontally projecting epimera. Eyes normally 

 developed. Antennular peduncle with male apjjendage very small, tuberculiform ; outer 

 flagellum forming a lamellar expansion at base. Antennal scale remarkably small, shorter 

 than basal part of flagellum, apex obliquely truncate. Legs subequal, densely setiferous, 

 with terminal part subdivided into a more or less considerable number of short articula- 

 tions, terminal claw quite obsolete. Caudal limbs in female partly obsolete, in male well 

 developed, natatory. Telson large, incised at apex. Inner plate of uropoda scarcely 

 shorter than outer ; auditory apparatus distinctly developed. 



Remarks. — This genus, first established by Kroyer, is chiefly characterised by the 

 rudimentary condition of the antennal scale, the presence in the female of a pair of small 

 but distinct epimera on the first caudal segment, and the peculiar reduction of some of 

 the caudal limbs in the female, finally by the form and large size of the telson. Besides 

 the three species described below, a fourth, Anchialus agilis, has been recorded by the 



