31(3 PEKCT SLADEN TEUST EXPEDITIOX. 



than correspondino" structures in P. nigromaculata. Palps stout and conical, abruptly 

 endinf in acute tip ; no trace of cilia (as found in P. nigromaculata) even when examined 

 microscopically. 



Ventral sette of four types, viz. : (1) slender gibbous setae with close-set spines placed 

 irreo-ularly (fig. 56 j ; (2) similar setse with spines arranged in whorls occurring after 

 the eleventh segment ; (3) " aristate " setse with long appendix ; (4) slender gibbous setae 

 differing slightly from (1). 



Locality. Saya de Mallia, C 12, 47 fathoms. Dredged with Slhenelais foliosa and 

 rmmmolyce gracilis ; " the bottom was muddy with a little shell matei-ial." 



Ihis species differs distinctly from P. nigromaculata and P. oerstedi in the characters 

 of the head, and especially in the possession of sessile eyes, pedunculate eyes only being 

 known in the other members of the genus. 



A more detailed description of the ventral setae may well be given here : — (1) The 

 gibbous appearance of this type is due to the enlargement of the shaft just below the 

 curved spinose tip. Spines close-set, fine, and extremely numerous. In the twelfth 

 segment these are succeeded by (2) another type of slender seta (fig. 56) in which the 

 spines are larger, less numerous, and arranged in whorls at rather wide intervals (this 

 kind of seta is familiar in P. nigromaculata) ; (3) " aristate " forms of a particular type 

 (fio'. 57) occupy the centre of the neuropodium, and occur throughout the body, 

 distinguishing the species very definitely from all others. The thick massive shaft ends 

 as visual in a hooked apex, and on the concave side occur short spines distinctly more 

 numerous than in P. nigromaculata. In the alveolus on the concave side of the tip 

 originates a long flexible appendix thickly beset with delicate processes. In P. nigro- 

 maculata the alveolus is occupied only by a few small spines. The ventralmost setae (4) 

 are again of the slender gibbous variety described as (1), but the tip is not so long and 

 has a more pronounced curve. 



Tamily Sigalionidse. 



Genus PSAMMOLYCE. 



This genus is characterised by elytra which leave the greater part of the back bare. 

 Both the elytra and the back are covered with papilUe modified for the retention of 

 small stony particles, wliich must of course vary vvith the habitat of the animal. Thus 

 in P. arenosa from the Meditei'ranean the animal is coated with fragments of volcanic 

 minerals like augite, while in the two specimens here described from coral islands foramini- 

 fera and coral fragments are characteristic. It is typical of the genus that the first pair 

 of elytra should be larger than the rest and overlap, covering the head ; only tlieir shape 

 sometimes differs, P. occidentalism Mcintosh, possessing narrow first elytra, while in 

 P. fjiensis they are prow-shaped. As for the elytra in general, Willey states that " they 

 are not safe objects for comparison," for they vary from segment to segment. In the 

 specimens described below, certain features of the elytra as a whole were found to be 

 characteristic of each species. The scanty material made it impossible to judge how far 

 the elytra vary in different individuals of the same species. Unfortunately, only single 

 specimens are found in most cases where this worm has been collected. 



