SOME AQUATIC WORMS, ETC. 175 



see these scales, the very long caudal branches with 

 their joints, and the sulcation behind the mouth, will be 

 sufficient to identify the specimen. 



6. CELETONOTUS MAXIMUS. 



The back and sides are covered with spines which are 

 often rather longer on the posterior region than else- 

 where. They are arranged in longitudinal parallel rows, 

 yet they often seem to be irregularly scattered, so that 

 the animal presents an untidy, dishevelled, and disrep- 

 utable appearance. The spines are minutely forked 

 near the free ends. The branching is very uneven and 

 is easily overlooked, one branch being very small, often 

 scarcely more than a minute linear projection. 



The ventral cilia are in two longitudinal lateral bands, 

 and the space between is clothed with short, hispid, re- 

 curved hairs, two or more long fine bristles projecting 

 from the same part beyond the posterior border, be- 

 tween the two caudal branches. 



7. ClLETONOTUS LAKTJS (Fig. 132). 



The whole upper surface is clothed with short, conical 

 spines in longitudinal rows, these appendages being re- 

 curved and not branched. They are often largest pos- 

 teriorly. The mouth is not beaded. The ventral cilia 

 are in two broad longitudinal bands near the lateral mar- 

 gins, and the intervening space often bears two addi- 

 tional parallel lines of cilia, which may be absent from 

 some specimens. These cilia, as in all the species, sub- 



