THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



[FOURTH SERIES.] 

 No. 96. DECEMBER 1875. 



LII. — On a Young Specimen of Pelagonemertes Rollestoni. 

 By H. N. Moseley, Naturalist on' board H.M.S. ' Chal- 



lenger.' 



[Plate XL] 



On June 5, 1875, in lat. 34° 58' N., long. 139° 30' E., about 

 halfway between Vries Island, Oosiraa, and Cape Sagaini, 

 the trawl was used by H.M.S. 'Challenger' in from 755 to 

 420 fathoms. A young specimen of a peculiar pelagic Nemer- 

 tean, which has been described by me (Ann. & Mag. Nat. 

 Hist. ser. 4, vol. xv. p. 165, March 1875) under the name of 

 Pelagonemertes Rollestoni, in honour of my friend and in- 

 structor Prof. Rolleston, was found by Dr. von Willemoes- 

 Suhm adhering to the net, and by him handed over to me for 

 examination. The adult specimen before procured and de- 

 scribed was in a similar manner found adhering to the trawl- 

 net after a deep-sea dredging by Dr. von Willemoes-Suhm. 



The animal was very much smaller than the one obtained 

 before, measuring only 13 millims. in extreme length and 

 11 millims. in extreme breadth, and about 1 millim. in ex- 

 treme thickness. It was in good preservation when found, 

 and living ; and being extremely transparent, much more of 

 its structure could be observed than in the case of the more 

 full-grown specimen. Unfortunately, an attempt to preserve 

 the specimen by treatment with perosmic acid and subsequent 



Ann. & Mag. N. Hist. Ser. 4. Vol. xvi. 27 



