226 THE GENEBA OF NEMERTEANS. 



splendidus (Keferstein) Barrois and the mediterranen one 

 Di^epanophorus rubrostriatus Hubr. 



The five parallel red lines on the back were present in 

 the very youngest stages observed (2 mm.); the number 

 of eyes increases with age. The largest specimen mea- 

 sured 6 cm. 



35. Drepanophorus serraticollis Hubrecht. 

 Synon. Drepanophorus nisidensis Hubrecht. 

 ?? Cerebratulus crassus Quatrefages. 



Distinct from the former by its system of coloration and 

 probably by an augmentation (in stages of a corresponding 

 age) of the number of small grooves which are perpendi- 

 cular to the transverse respiratory groove. 



The back is yellow (in a very rare variety this becomes 

 dark brown) the margins of the body are white or pinkish. 

 A thin whitish patch divides the yellow colour of the back from 

 the vinous red mixed with yellow which is characteristic 

 for the head. Two specimens attained the considerable 

 length of 12 cm. with a width of 10 — 12 mm. In this 

 species as in the former the external opening of the ciliated 

 duct , leading into the rounded posterior ganglionic lobe , 

 is situated behind or on a level with the ganglion. The 

 duct itself is short. 



I doubt whether Quatrefages' C. crassus had an unarmed 

 proboscis as he positively describes it to have had. There 

 is great probability of his specimen having either belonged 

 to this species or to Amphiporus pulcher. 



Familia Tetrastemmidae. 



Eyes four. Respiratory grooves not branched. Respiratory 

 lobe of the ganglion apparently in regressive metamorphosis. 



Genus Tetrastemma Ehrenberg. Generally of small size, 

 body capable of considerable lengthening and shortening. 

 Eyes generally small in comparison to the width of the 

 body. 



Notes irom the Leyden ]M.useum. 



