108 THE VOYAGE OF H.M.S. CHALLENGER. 



the cruise, and, secondly, because of the pale semitrausparent appearance which suggested 

 its specific name. It seems better, however, to omit this and to leave the depth from 

 which the specimen was taken an open question ; there was, so far as I can ascertain, 

 no objective evidence that the animal had been taken at the surface, and in the only 

 two cases in which examples of this genus have been obtained the dredge or trawl had 

 been to a great depth. Professor Steenstrup's five specimens of his Bolitasna micro- 

 cotyla, a form nearly allied to this, were all taken in the surface net with Medusse and 

 other pelagic organisms at very distant localities. 



The question as to the specific identity, or otherwise, of this form with that 

 described by Verrill seems at present to admit of no decision ; the extent of variation in 

 a genus consisting at present of only two specimens is, of course, quite uncertain, the 

 more so as these belong apparently to difierent sexes. It seems, therefore, that the 

 interests of science will be best served by recording the two as distinct, though I have a 

 strong suspicion that they will eventually be proved to be identical, and had the knowledge 

 of Verrill's species come to me in time I should not have proposed a new name. 



The present type resembles Bolitsena, Steenstrup, in the gelatinous consistency of 

 the body, in the presence of a median septum in the branchial cavity, in the wide 

 opening of the mantle, which extends to just behind the eyes, and in the preponder- 

 ance of the third pair of arms. They difler, however, in a considerable number of im- 

 portant characters. In Bolitsena microcotyla the distance from the eye to the extremity 

 of the arms is somewhat greater than from the eye to the end of the body, whereas in 

 Eledonella it is only about half as great ; and whilst in Bolitsena there are fourteen 

 small widely separated suckers on the longest arm, in Eledonella there are sixteen larger 

 ones closely placed. In Bolitsena the colour is a brownish -purple, with irregular dark 

 brown mottlings, and a delicate web extends about halfway up the arms, whUe in Eledon- 

 ella the colour is almost white, with elongated oval brownish spots, and the web extends 

 only one-fourth up the dorsal arms, and to a somewhat less extent between the others. 



The genus Eledonella furnishes one of the instances in which closely similar, if not 

 identical, forms occur both in the Western Atlantic and the Western Pacific (compare 

 pp. 184, 223). 



Ja'petella} Hoyle. 



Body gelatinous in consistency and semitrausparent, and more or less oblong in 

 form. Mantle-omening very wide. Siphon provided with a valve. No median 

 septum in the branchial cavity. 



Arms unequal, and the longest only about equal in length to the body. Umbrella 

 small, and the suckers arranged in a single series. 



1 Named in honour of Professor Japetus Steenstrup, whose brilliant researches have added so much to our 

 knowledge of this group, and who examined this specimen and the one just described with peculiar interest. 



