POTTS— POLYCH.ETA. 313 



closely resembles the figure given liy Bcnham of this species in the ' Cambridge Natural 

 History,' vol. ii. PolycliDeta, fig. 156. 



The elytra are very small, decreasing in size posteriorly. They are smooth, veith 

 entire borders as always in Lepidasthenia, and are oniamented with black and white 

 spots, resolved under the microscope into small aggregates of cells containing pigment. 

 The dorsum is sometimes thickly sprinkled with the white masses of pigment also. 

 The dorsal cirri, in the fi.rst three segments bearing them, are distinctly longer than the 

 parapodium, but after this region only their slender filiform tips stretch beyond the 

 ventral setse. Tiie notopodium is represented only by a small pig^iiented hump and the 

 dorsal aciculum. 



The succession of the ventral setae (fig. 32) is very characteristic. Only a single 

 type is found ^^ith the bifiu-cate tip characteristic of the genus. Throughout, the 

 uppermost setae are the largest, and the size decreases ventrally ; but whereas anterior 

 to the twenty-first segment the superiority of the uppermost setae is not distinctly 

 marked posteriorly, they become very much enlarged, acquiring at the same time a 

 dark brown colour, which contrasts markedly with the golden hue of the other setae. 

 The apex i-emains bifurcate in many, but may become single, and in the enlarged setae 

 the spiniferous area becomes less prominent, the spines being greatly reduced. In the 

 jjosterior region of the woi-m the most dorsal setae again approximate to the average size. 



There seems little doubt that this worm is a southern form of the Mediterranean 

 L. elegans, described by Grube. The colour-pattern is remarkably similar (though 

 variable in each case), and, in addition, the curiously large setae occur in tlie notopodium 

 of both. Palps and tentacles appear to be slightly longer than in the Zanzibar form ; 

 but the elytra in Naples specimens are closely similar in size, though lacking the orna- 

 mentation of flecks of pigment. 



Locality. Wasin, Zanzibar, dredged in 10 fathoms ; 2 specimens, collected by 

 Mr. C. Crossland. 



23. Lepidasthenia microlepis, sp. n. (Plate 19. fig. 17; Plate 21. fig. 52.) 



Measurements. Appears complete, but may be regenerated. Length 28'5 mm., 

 breadth 5 mm. with setae ; no. of segments 46 ; 19 pairs of elytra. 



Palps and tentacles very short and stumpy ; palp twice as long as median tentacle, 

 and the median tentacle a third longer than the lateral. 



Elytra quite rudimentary *, only just capping the elytrophores, with exception 

 of first pair, Avhich cover most of the head (fig. 17). All after these are found in the 

 same state of development, marked by edging of brown or chocolate pigment. 



Notopodium only represented by the aciculum. In ventral setae (fig. 52) bifurcate 

 type characteristic of the genus only found in inferior setae of seventh segment. In 

 others apes simple ; spur sometimes developed just under apex. 



Dorsal cirri stumpy, like tentacles, composed of two articulated joints. 



Locality. Hulule, Male Atoll, Maldives. 



* This might well have been considered as an individual regenerating its elytra, if the tendency to reduction in 

 size were not characteristic of the genus, and if the attachment of the elytra were less secure in Lepidasthenia ia 

 general and this species in particular, 



45* 



