POLYCrLETA. 259 



fig. 48). The ciliated cushions or cteuidia (McIntosh) on the upper surface of the 

 foot beneath the cirriform branchia are the same as in Sth. boa, but the disposition ot 

 stvlodes is different, particularly as regards the two long stylodes which proceed from 

 the base of the ventral cirrus in Sth. zeylanica (Plate II., fig. 48). 



Sthenolepis, n. gen. 



The genera Thalenessa and Leanira are characterised by the presence of a very 

 small teutaculum impar inserted directly upon the prostomium, not borne upon a 

 ceratophore. The compound setaa of Thalenessa are a variety of the falcigerous type 

 with bidentate appendices; those of Leanira are spinigerous. 



Sthenelais and Sthenolepis, n. gen., are characterised by the presence of a long 

 tentaculum impar borne upon a ceratophore which is provided with a pair of 

 spatulate appendages. The compound setas of Sthenelais are falcigerous like those 

 of Thalenessa ; those of Sthenolepis are spinigerous as in Leanira. 



All the species of Leanira described by Professor McIntosh in the " Challenger" 

 collection are to be ranged in the genus Sthenolepis. In this genus the scales are 

 generally smooth. 



Sthenolepis japonica (McIntosh) Plate II., fig. 49. 



Leanira japonica, McIntosh, ' "Challenger" Polychseta,' 1885, p. 154. 



A headless posterior fragment of a Sigalionid worm, labelled " L,eanira sp.," was 

 dredged at Station XXXV., off Galle, 7 fathoms. An anterior fragment of the same 

 species with same locality and date was contained in another bottle in company with 

 < rlycera lancadivcp. 



The different preservation of the two pieces gives them a different aspect, but the 

 structure of the parapodia shows that they belong to the same species. The thin 

 translucent smooth elytra embrace the body so closely as to be inconspicuous ; in 

 front they meet in the middle line and overhang the head ; further back they leave 

 the mid-dorsum exposed and then approximate again. 



The long tentaculum, accompanied by a pair of equally long tentacular cirri, projects 

 straightly and stiffly forwards ; the spatulate appendages are nearly as long as the 

 ceratophore ; at the base of the latter on each side of the prostomium a small eye is 

 visible from above. The ends of the parapodial rami are furnished with a rich growth 

 of stvlodes ; the dorsal setce are very numerous, long, slender, and transversely 

 fringed ; from the dorsal end of the ventral ramus a compact tuft of about 20 

 spinulose simple setse issues ; the rest of the ventral setae are compound spinigerous, 

 the appendices are not very long and present a peculiar intrinsic laminated structure. 

 Between the cirriform gill and the dorsal fascicle are three ctenidia. The ventral 

 cirrus has a rounded protuberance some distance beyond its insertion (Plate II., 

 fig. 49). The body is slender, the anterior region having a width of 2 - 5 minims. 

 across the body, 4 millims. across the setaa. 



2 L 2 



