SIBOGLINUM EXILE 309 



cephalic lobe, which has a blunt tip. The epidermis of the cephalic lobe is 

 not especially rich in gland cells. The long thin tentacle is attached much 

 nearer to the tip of the cephalic lobe than to the hind edge of the protosoma. 

 The comparatively short pinnules (75/г long) are arranged in two longitudinal 

 rows at some distance from one another (Fig. QQJ33Z)). 



The distance between the tip of the cephalic lobe and the bridle is approxi- 

 mately half that between the bridle and the hind edge of the mesosoma. The 

 part of the mesosoma in front of the bridle is divided into two almost equal 

 parts by a slight transverse ventral groove (Fig. QQ133/i-C). The keels of 

 the bridle, which lie on ridges, are almost colourless, thin and tapering. On 

 the dorsal side the keels do not meet, but on the ventral side they fuse. 

 Characteristically, the keels are crossed by thin grey cuticular rodlets 

 (Fig. QQ133A-C). There is a pair of small indistinct glandular patches on 

 the ventral side in front of the bridle, and flask-shaped glands, visible through 

 the body wall, occupy the whole mesocoele behind the bridle (Fig. GV1335, 

 C). The boundary between the mesosoma and metasoma is a simple transverse 

 groove. 



In the metameric section of the metasoma there are 60-70 pairs of more 

 or less equal papillae. The anterior ones are comparatively small, rounded 

 and crowded close together (Fig. QQJ33y4, C); they increase in size towards 

 the end of the series. There is one pyriform gland per papilla and no plaque. 

 The nonmetameric section of the trunk is long and its epidermis is rich in 

 gland cells, forming glandular areas and patches which are whitish in 

 reflected light. Here and there one encounters roundish contracted papillae 

 (Fig. RR133^). 



There are three girdles, two lying about 1-2 mm in front of the third. 

 The first and third girdles are widely broken on the ventral side, the second 

 on the dorsal (Fig. RR133Z?, C). Immediately behind the last girdle is found 

 a large plaqueless conical ventral papilla (Fig. RR133C). The toothed 

 platelets lie in a single row on broad cushion-like ridges. They are elongated 

 and Ungulate ('biscuit-shaped' — see p. 226) (Fig. RR133D). The anterior 

 and posterior groups of teeth are equally well developed (Fig. RR133£). 

 Most of the toothed platelets are 1 1— 17/x long, but there are sometimes small 

 underdeveloped platelets. 



The postannular region of the trunk is long. The metamerically repeated 

 ventral papillae are small and lack plaques. Opposite each papilla there is a 

 small but well-defined glandular dorsal shield (Fig. RR1337 7 ). 



All five individuals turned out to be females and one of them appeared 

 to be a young immature animal. Mensuration gave the following results (mm) : 



