THE GENERA OF NEMERTEANS. 231 



numerous, some of them placed far back, over the lateral 

 nerve-truuks from which they are innervated. 



A great extent of colour variation prevails in this spe- 

 cies. The extremes were represented by a dark olive , a 

 bright brick-red and an orange specimen which come under 

 observation at different occasions. 



48. Nemertes antonina (Quatref.) Hubr. 

 Synon. Polia antonina Quatrefages. 



Characterized by its extreme tenuity which gives it quite 

 a threadlike appearance. Its uniform light carmine colour 

 is another peculiarity by which it is easily recognizable. 

 The proboscis is thin in accordance with the rest of the 

 animal , the central stylet is rather weak and seems not 

 unfrequently to be missing; the ganglionic lobes of both 

 sides are united by a broader commissure than in any other 

 species of Nemertean. 



49. Nemertes marioni n. sp. 



Basis of the central stylet spindle shaped , long and 

 thinned towards both ends. In external habitat, colour etc. 

 it resembles Amphip. lactijioreus. Here too the ventral 

 commissure of the ganglia is of considerable thickness. 

 There are 13 to 15 small pigmented eyespecks on each 

 side of the head, many of them curiously indefinite of contours. 



50. Nemertes neesii (Oersted) Mac Intosh. 



One specimen was observed which unluckily got mislaid 

 before further examination was possible. However the cha- 

 racteristic longitudinal brown lines on the anterior part of 

 the trunk etc. render it almost certain that this species is 

 an inhabitant of the Mediterranean, though certainly rare 

 at Naples. 



The species which have here been provisionally described, 

 will ere long be more circumstantially treated of iu a 



Notes Iroixi the Leyclen ]VIuseuin. 



