192 THE VOYAGE OF H.M.S. CHALLENGER. 



(•omparatively short aud thick, with the hist joint by far the hirgest. The male appendage 

 also exhibits a very similar aspect. 



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

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

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

 margins apparently fringed with setae 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 setae. Thus, the scale is, in reality, formed upon the same type as that in the other 

 species of the present genus, but is truncate oblic_[uely to such an extreme degree, that 

 the inner linguiform-produced coruer 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 whereas the outer corner has withdrawn to very near the base.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 

 flagellum 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 antennulse had been broken off near tlieir leases. 



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

 of Decapoda and other Crustacea, taken off the entrance to Port Phili[i, Bass Strait. 

 The locality is given below, as follows : — 



Station 161, April 1, 1874 ; lat. 38' 22' S., long. 144° 36' E.; depth, 33 fathoms; 

 sand. 



Genus 5. Anchialus, Kroyer, 1861. 



Anchialus, Kroyer, Nat. Hist. Tidsskr., 2'''" Rxkke, Bd. i. 



Genefic Cltaracters. — Form of body somewhat different in the different species. 

 Carapace more or less developed, with frontal margin produced in the middle. Fii-st 

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

 developed. Antennular peduncle with male appendage 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 shoi't articula- 

 tions, terminal claw quite obsolete. Caudal limbs in female jiartly 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 



