ON A NEW SPECIES OF SCLEROCHKILUS. 



411 



nuchal organ, which, when everted, forms a sausage-shaped mass of considerable 

 size (see fig. 7). 



The peristomium is a single achsetous ring, incomplete ventrally. 



The first two or three chsetiferous segments are usually bi-annulate, but the re- 

 maining segments, except a few of those last formed, are subdivided into four rings. 



The stronger, curved chsetse (" acicula " of Saint -Joseph) on each side of the first 



Text-fig. 3. — A, B, 0, D. Chnitae from the first notopodium of a specimen of Sclerocheilus 

 minutus, 18 "5 mm. long. ( x 200.) 

 B'. A chaeta which had not come into use, from the first notopodium of a 

 specimen 1 1 mm. long. ( x 300. ) 



chsetiferous segment are undoubtedly part of the armature of the notopodium, and 

 form a portion of the anterior series of chsetse. The following is a brief account of 

 the chief chsetal characters resulting from a study of specimens 11 to 18 '5 mm. long. 



The first notopodium contains three kinds of chsetse : — - 



(i) Strong and almost straight chsetse, which taper distally to a fine point 

 (text-fig. 3, A). Each of these chsetse is about '5 mm. in length and 15-20/x in maximum 

 diameter, and in all the specimens examined only the tips # of these chsetse project 



* Not more than about "04 mm. 



