REPORT ON THE NEMERTEA. 29 



"The occurrence of a peculiar burnt-sienna colour in many very different pelagic 

 animals is remarkable. With many the colouring may be explained as protective 

 resemblance to the oceanic seaweeds. For its occurrence in others, such as Salpa and 

 Pelagonemertes, in an otherwise hyaline body, there may be some common cause, possibly 

 also protective. 



" Diagnosis of the genus Pelagonemertes, H. N. M. : — Body leaf -shaped, gelatinous, 

 hyaline. The anterior extremity of the body broad and abrupt, the posterior narroiued 

 to a point. Tlie digestive canal with thirteen pairs of lateral ramifications, as in 

 Dendrocoela. Integument thin and hyaline, with a thin muscular tunic immediately 

 beneaih it, consisting of external circidar and internal longitudinal fibres. The animal 

 free-swimming, oceanic." 



Moseley's second article, which appeai'ed nine months later, was again accompanied by 

 figures, which will be found reproduced on PI. I. figs. 23, 28-31. The contents were as 

 follows : — 



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

 Vries Island, Oosima, and Cape Sagami, the trawl was used by H.M.S. 'Challenger' in 

 from 755 to 420 fathoms. A young specimen of a peculiar pelagic Nemertean, which has 

 been described by me (Ann. and Mag. Nat. Hist., ser. 4, vol. xv. p. 165, March 1875) 

 under the name of Pelagonemertes Rollestoni, in honour of my friend and instructor 

 Professor Eolleston, 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 

 described 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 mm. in extreme length, and 11 mm. in extreme breadth, and about 1 mm. in extreme 

 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 action of glycerine failed, and the specimen perished. 

 The trawl came up late in the evening, when only an hour of daylight remained ; the 

 examination made was thus a hasty one. 



"The animal showed the same feeble pulsating movements which had been shown by 

 the adult. 



" The external gelatinous investment of the body was perfectly transparent, and none 

 of the peculiar corrugations of a thin superficial epidermic layer were visible as in the 

 adult specimen. The contours of the body were well preserved, including those of the 

 hinder portion, which was broken in the specimen before obtained. 



" The forepart of the body is wide, with rounded margins ; the posterior narrowed, 

 with a series of indentations on its margin corresponding to the successive pairs of 



