304 CEYLON PEARL OYSTER REPORT. 



The body is narrowed anteriorly (in the region of the scuta ventralia) and 

 attenuated behind ; in the middle region it is inflated and somewhat varicose ; 

 segments about 100, length about 85 millims., width of thorax in front 4 millims., 

 behind the scuta 5 millims. (Plate VI., fig. 160). Counting the composite sternite of 

 the 2nd, 3rd, and 4th segments as the first scutum, there are eight clear scuta 

 followed by a rather ill-defined ninth. After this there is no trace of further scuta, 

 the median ventral tract separating the tori uncinigeri is wide and smooth, and the 

 length of body between the successive tori gives the worm a remarkable appearance. 

 In the first torus the uncini are mostly 6-dentate, the sixth tooth sometimes large, 

 sometimes rudimentary, and many uncini in the same torus are 5-dentate (Plate VI., 

 figs. 161 and 162). In the fourth torus not one 6-dentate uncinus was observed, only 

 5-dentate uncini with a sprinkling (about 5 per cent.) of 4-dentate uncini. In the 

 biserial tori only 6-dentate uncini were found in both rows (Plate VI., fig. 163). An 

 abdominal pinnule contained 7-dentate uncini, the seventh tooth usually small and 

 occasionally obsolescent, but clear enough to characterise the region. 



In ventral view (Plate VI., fig. 160) this worm presents distinguishing features 

 depending upon the size and limited number of the scuta ventralia, the absence of 

 subdivided scuta behind the main series, and upon the divarication of the meta- 

 thoracic tori. In the character of the uncini the species corresponds closely with 

 Loimia montagui, Gr., as described by Marenzeller (' Siidjapan. Ann.,' 1884, ii., 

 p. 9, reprint), who, however, does not describe a definite succession of uncini such as 

 I have noted above, namely, the 6-dentate uncini of the first torus, followed by a 

 reduced denticulation in the succeeding uniserial tori, and this again by an increased 

 denticulation in the biserial tori and a further increase in the 'abdominal pinnules. It 

 agrees with L. montagui again in the triangular shape of the lateral lobes of the 

 third segment and in the presence of a whitish glandular tract on each side of the 

 dorsal surface over the capillary fascicles, extending from the gill-region to the eighth 

 setigerous segment, where it ends in a point. 



Although von Marenzeller records eleven scuta ventralia for Loimia montagui 

 from Japan, and Grube ten for the example described by him from the Philippines ; 

 the former author specially notes that the most sharply circumscribed scutes are 

 those from the second to the eighth inclusive, which accords with the variety from 

 Palk Bay. Neither Grube nor von Marenzeller refers to the tube, which, in the 

 case of Terebellidse, may or may not be a matter of importance. Nor is any 

 information given as to the nature of the locality. Both of these points, in the 

 present instance, have a special interest, bearing upon the identification. 



Loimia varieguta (Grube). 



Terebella variegata, Ehrb., ' Monatsber. Ak. Berlin,' June, 1869, p. 30 of reprint; Grube, 

 1878, 'Ann. Semp.,' p. 227. 



One specimen in a thin membranous tube encrusted with shell-fragments and 



