SIBOGLINUM INERAIE 



269 



There is no definite zone of enlarged papillae but some moderate-sized 

 papillae are scattered in the region in front of the girdles; similar papillae 

 are to be found in the genital region. There are normally two girdles, but 

 very rarely three may be seen. This condition is probably brought about by 

 overlapping of the two halves of the first girdle, because each normally 

 consists of two lateral semi-circular bands, sometimes slightly overlapping. 



Fig. 133. Siboglinum inerme: A - front end of the body from the dorsa , and, В -from the ventral 



side. 



с - cephalic lobe ; ci - glandular girdle ; со - dorsal ciliated band \f— keel of the bridle ; ms - meso- 



soma ; mts - metasoma ; ps - protosoma ; s 1 - groove between the protosoma and the mesosoma ; 



s 2 - groove between the mesosoma and the metasoma ; sv - ventral sulcus ; / - tentacle. (After E. C. 



Southward and A. J. Southward, 1958b.) 



Whatever the situation the girdles are always close together, and each has a 

 single row of toothed platelets 10-12/x long. These each bear two groups of 

 teeth, the anterior group smaller than the posterior (Fig. A133Z)). The post- 

 annular region possesses dorsal shields and solitary ventral papillae. 



The tentacle is 3 mm long; the fore-part of the body reaches a length of 

 0-7-0-96 mm; the breadth of the mesosoma is с 0-15 mm; the overall 

 length of the body varies from 13-5 to 25 mm; the metasoma in one female 

 was 14 mm long, of which the preannular region occupied 5 mm. 



The spermatophores are 50-60/x long. 



