242 PART II. SYSTEMATIC ACCOUNT 



cylindrical mesosoma by an annular groove which lies nearer to the base of 

 the tentacle than to the bridle. The cephalic lobe is small and conical and the 

 point of attachment of the long tentacle (which is naked of pinnules) lies a 

 little to right of the mid-ventral line. The front edge of the mesosoma is 

 scarcely, but nonetheless perceptibly, thickened, forming a sort of annular 

 rim (Fig. 122yt/, B), and the bridle lies one-third of the length of the mesosoma 

 back from this. Its delicate keels, fused together ventrally, lie on narrow but 

 distinct cutaneous ridges (Fig. \22A) and they reach their greatest thickness 

 in their lateral and dorsal parts, while on the ventral side they are consider- 

 ably thinner. Their dorsal ends are separated by a wide gap (Fig. 1225). A 

 glandular belt in the form of a pair of latero-ventral, muddy-brown areas of 

 epidermis immediately adjoining the hind edge of the bridle, encompasses 

 the mesosoma, while the ventral surface is scored by a perceptible, but 

 shallow median furrow. The hind edge of the mesosoma has a mid-ventral 

 notch and arches backwards on the dorsal side (Fig. 122Д B). 



The metameric section of the metasoma carries large rounded papillae 

 without plaques. In the male there were 51 of these on the right side and 50 

 on the left, while in the female there were 57 and 62 respectively. Through 

 their walls the ducts of pyriform glands are visible, two per papilla for the 

 most part, towards the front, but there is only one gland in each papilla farther 

 back (Fig. \22A). The well-developed dorsal ciliated band begins at the front 

 edge of the metasoma (Fig. 1225). In the female a few small scattered 

 rounded papillae without plaques are situated behind the genital aperture 

 (Fig. 122C), and these papillae differ in no way from those just in front of the 

 girdles. In the male, however, in the zone of thickened papillae, two slightly 

 prominent papillae may be discerned. Clearly there is no sharply defined zone 

 of thickened papillae in this species. The two adjacent girdles are of the 

 usual kind and both are interrupted on the dorsal as well as on the ventral 

 side (Fig. \22D). The yellowish elongate-oval toothed platelets are just a 

 little narrower at the front, without any noticeable central constriction. They 

 are arranged in one or two rather irregular rows (Fig. \22E) and possess 

 both groups of teeth, though the anterior group is only feebly developed 

 (Fig. \22F). The platelets measure 9-12ju by 3-4/x. 



The tentacle is not less than 2-5 mm long, and the fore-part of the body 

 с 0-8 mm; the breadth of the mesosoma is 0-13-0T6 mm; the metameric 

 part of the preannular region of the metasoma is 3 mm long, the whole pre- 

 annular region, 7-8 mm. 



The tube is rather hard for most of its length, with firm walls, but the very 

 front and back parts are flexible. The transparent front section, with soft 



