294 J. H. ASH WORTH. 



and the nepliridia are formed on exactly the same plan as 

 those of Scalibregma, each nephridiura being a delicate 

 tube, the excretory portion of which is once bent upon itself. 

 S. Joseph believes that the nephridia act as genital ducts, 

 but this seems improbable, if not impossible, as the lumen of 

 the nephridium is too small to permit the passage of a ripe 

 ovum (judging from S. Joseph's figures, pi. v, figs. 137, 

 142j. The animal derives its name from two plate-like pig- 

 mented structures on the head, which Grube believed to be 

 "horny'' and protective, but S. Joseph describes them as 

 eyes.^ 



This animal is most closely allied to the gill-less forms 

 of Scalibregma (Pseudoscalibregma), with which it 

 agrees in general shape, in the characters of the prostominm, 

 fui'cate setae, nephridia, and nervous system, but differs from 

 them in possessing strong sette in the second segment, the 

 presence of eyes (?), and the absence of dorsal cirri. 



According to S. Joseph (1894, p. 113), his new species 

 Lipobranch ius intermedins is very similar in ahnost all 

 respects to Sclerocheilus minutus, with the exception 

 that the former bears no eyes upon the head and no cirri 

 upon the parapodia. It seems to me that this animal is not 

 a Lipobranchius ; it differs from that genus in at least two 

 important respects, viz. the shape of the prostominm and the 

 possession of strong acicular seta3 in the first parapodium. 

 This animal is more nearly allied to Sclerocheilus than to 

 any other member of the family of Scalibregmidse, It may 

 for the present be named Asclerocheilus intermedins, a 

 name Avhich indicates its relationship to Sclerocheilus, 

 and at the same time reminds us that the pigmented plates, 

 the distinctive character of the latter genus, are absent from 

 the former. 



It would have been better had the preparation of the 

 following table of characters and classification been post- 



• S. Joseph (p. 105) stales tliat tliese pigmented areas occur on the dorsal 

 surface of the head; while Grube describes and figures them (p. 50, and Taf. 

 V, fig. 3 i) on the ventral face of the prostoniium near the nioulh. 



