212 THE GENERA OF NEMERTEANS. 



the coloration of back and belly ; it is uniform all over. 

 The margins of the body are white, so are the margins of 

 the cephalic fissures. Exceptionnally the white margins 

 may sometimes disappear {PI. angulata 0. F. M.). No 

 eyes. An anal papilla was observed in most of the spe- 

 cimens , in some of which it seemed even to have become a 

 short caudal appendage. This species was first described 

 by Renier. Blainville afterwards created a confusion by 

 figuring this species under the name of C. hilineatus , 

 which had been employed by Renier for quite a distinct 

 species as will be noticed further down. Delle Chiaje did 

 not correct Blainville's error and moreover brought these 

 two species together with Renier's Tubula'nus (a true Cari- 

 nella) in his genus Ophiocephalus , the third species of which 

 was 0. murenoides (probably identical with Mac Intosh's 

 Borlasia elizabethae). C. marginatus seems to extend from 

 Norway to the Mediterranean. 



11. Cerehratulus pantherinus n. sp. 



This species may on a superficial inspection be easily 

 confounded with the foregoing by its colour and the two 

 white lines alongside of the body margins. Still I found 

 it to differ constantly in no unimportant points: inter- 

 nally, by the red colour of the nervous tissue which was 

 constantly much paler than in C. marginatus or in any 

 other species of the same genus (less haemoglobine con- 

 tained in the nervous tissue) ; externally by the spotted or 

 marbled character which the brownish grey ground-colour 

 afi'ects on the head and the anterior portion of the trunk. 

 The belly is generally of a lighter colour than the back. 

 The margins ot the respiratory fissures are never white as 

 in C. marginatus , at the same time they seem to be shorter 

 than in this species and the head more truncated. Finally 

 there was a marked difference in the physiological sensiti- 

 veness of the two species towards desoxygenated seawater. 

 One specimen entirely devoid of pigment, was of a uni- 

 form pale yellow. 



Notes from tlie Leyden IMuseuizi. 



