THE GENERA OF NEMERTEANS. ^17 



triangle pointing forwards , wliicli is already figured by 

 Huschke. This species seems to be more compressed than 

 others of its congeners. I failed to detect any caudal 

 appendage. The proboscis contains urticating elements 

 (0.036 mm. without thread). 



20. Cerebratulus hepaticus n. sp. 



Under this name I wish to describe a species which is 

 represented in Naples by numerous specimens , often attaining 

 a considerable size (up to 8 or 10 mm. in width). The 

 ground colour which is subject to much variation is gene- 

 rally a mixture of grey , red and brown ; the hinder part of 

 the body is generally distinguished from the anterior por- 

 tion by its brick red colour , which is due by transparency 

 to the coloured cells in the wall of the intestine. The proboscis 

 when protruding is transversely banded with brown in 

 the portion which is nearest the head. The tip of the 

 snout is yellow ; the anterior parts of the back and throat 

 are often marked by a few light green or yellowish patches, 

 irregularly distributed. The respiratory fissures on both 

 sides of the head are very long , so is the head itself. In 

 fresh specimens with uninjured tails a small caudal appen- 

 dage which did not seem capable of much extension was 

 sometimes noticed. The proboscis is provided with urti- 

 cating elements (rarely longer than 0.013 mm. , thread 

 not included). 



21. Cerebratulus urticans (J. Muller) Hubr. 

 Synon. Cnidon urticans J. Mull. 

 Meckelia » » 



The average size of the specimens belonging to this 

 species was 2 or 3 dm. in length and 8 or 10 mm. in 

 breadth. They are characterized by the proboscidean sheath 

 bulging out in the median line of the dorsum, especially 

 in the posterior half of the body, where transverse constrictions 



^otes trom the Leydeii INXuseuzn. 



