P0LYC1LETA. 301 



The branchire (as in Lanice triloba, Fischli) show very clear-cut dichotomous 

 ramifications, the main stem of each gill dividing near the base into two main 

 branches. In the biserial tori the uncini of the two rows are alternate and opposite, 

 (i.e., base to base), those of the anterior row progressive, of the posterior row 

 retrogressive. In Lanice triloba, the uncini of the biserial tori are inverted 

 (i.e., vertex to vertex), as in Loimia, though in structure they resemble the uncini of 

 Polymnia. 



Loimia annulifilis (Grube) Plate VI., figs. 153 and 154. 

 Terebella annulifilis, Grube, 'Ann. Semp.,' 1878, p. 225. 



Locality : Galle shore, under stones. Eight specimens. 



Tube encrusted with coarse, rather large shell and coralline fragments up to 8 millims. 

 or 9 millims. in diameter. In most specimens the body-wall of the dorsal thoracic 

 region has ruptured, and a coil of the gut is protruding. Diameter of thorax up 

 to 9 millims.; length of body about 150 millims.; abdomen coiled; more than 

 200 segments. 



Uncini from the first torus, 5-dentate ; from the third torus, 5-dentate (Plate VI., 

 fig. 153); from the sixth, 5-dentate, the fifth tooth becoming smaller and in some 

 uncini obsolescent ; from the ninth torus, 4-dentate in both rows ; from the twelfth, 

 4-dentate ; from the sixteenth, 4-dentate ; from the twenty-seventh torus (which is 

 borne upon the eleventh abdominal pinnule), 4-dentate. From these enumerations 

 it follows that the uncini of the first six uniserial thoracic tori are 5-dentate, of the 

 last ten biserial thoracic tori and of the uniserial abdominal pinnules 4-dentate. No 

 such distinction is recorded by Grube among the five species of Loimia described by 

 him from the Philippines. In some of the uncini from the anterior tori there seem to 

 be indications of a sixth tooth, and in one uncinus from the first torus there are six 

 distinct teeth. 



The first pair of arborescent branchiae greatly exceeds the second and third in size, 

 quite overshadowing them. Seen with low magnification, they present a densely 

 racemose or finely tufted appearance, due to the fact that the digitations arise in 

 groups from the main stem and thicker branches, curving inwards like the half-closed 

 fingers of a hand. 



According to the accepted interpretation of the anterior complex of the Terebellidse, 

 the buccal segment is destitute of appendages and sense-oigans (segmentum buccale 

 nudum), but is produced ventrally into a large free labial fold, which closes the 

 ventral opening of the horse-shoe-shaped collar or epistome formed by the prostomium 

 surrounding the mouth above and in front. The hinder portion of the prostomium 

 looks uncommonly like a cephalic segment and carries the tentacular cirri, which are 

 ringed with purplish colour as in Grube's Loimia annulifilis. The buccal segment is 

 the first body-segment, and is here practically non-existent above, though represented 

 below by the prominent labium. The second body-segment is the first branchiferous 



