POTTS— POLTCH^TA. 345 



Pamily AcoetidaB. 



Genus PANTHALIS. 



26. Panthalis nigromaculata, Grube. (Plate 19. fig. 18 ; Plate 21. figs. 53-55.) 



Grube, Annulata Sempeiiana, 1878, p. 50j pi. 4. fig. 2 ; Willey, in Herdman, Ceylon Pearl Oyster 

 Report, pt. iv. 1905, p. 255. 



Measurements. Anterior fragment 26 mm. in length, 3 mm. in breadth behind 

 pharynx, and contains 75 segments. 



This species is easily recognised by the black or chocolate spot in the middle of each 

 elytron, from whicb it derives its specific name. The arrangement of the eyes, whicli 

 is apparently peculiar in P. cerstedi also, is not easily made out. At each side of the 

 head (fig. 18) is a large pigmented prominence in no way separated from the head 

 itself, which Grube regarded as the eyeatalk fused to the head. This is surmounted 

 anteriorly by a whitisli conical papilla standing oat free, and identified by Grube as the 

 lens of the eye. Whether this is the correct interpretation cannot be decided at present, 

 because tbe head of the worm here described was not specially well preserved, and only 

 one specimen of it was collected. Two very minute black spots are situated on the 

 posterior border of the liead, as Grube notes, and are probably eyes. 



In his description of the ventral setae of P. nigromaculata Willey states that the setaj 

 known as " peuicillate " are absent. In my specimen I have found this type in every 

 foot examined. The succession here made out is dorsal to ventral as follows : — 



(1) Almost straight setae M'ith few spines arranged in whorls (fig. 53). 



(2) " Pencillate " seta? (flig. 54). These are derived from the first by the thickening 

 of the shaft, the reduction of the long, slender tip, almost to an appendage, coming olf 

 asymmetrically from the shaft, and the concenti'ation of spines round the base of this 

 appendage. This type hardly succeeds but rather comes side by side with the preceding. 



(3) " Aristate " setse (fig. 55). These appear to be formed from the " penicillate " 

 form by the thickening of the shaft and increase of asymmetry. The spines on its 

 apex are reduced in number, and the appendage is entirely lost tbough its articulation 

 remains. In the other species of this genus here described a long flagellate appendage 

 is retained in the " aristate " type, and an occasional seta was noticed here which seemed 

 to bridge the gap between types (1) and (3), having the bulk and shape of the first but 

 with a long spinose tip. 



(4) The slender inferior setse of the parapodium are intermediate in character between 

 types (1) and (2), but moi-e closely approximate to the " penicilhite." 



Locality. Goidu, Goifurfehendu Atoll, Maldives. 



27. Panthalis edriophthalma, sp. n. (Plate 19. fig. 19 ; Plate 21, figs. 56, 57.) 

 Two anterior fragments, one with 31, the other with 41 segments, the latter measuring 



11 mm. long and 5 mm. broad. 



Head spherical, divided by median longitudinal line. Eyes two pairs, sessile, anterior 

 pair rather larger, both distinct pigment masses situated quite on lateral border. 

 Median tentacle lost; lateral slender structures gradually tapering to tip, rather longer 



