Mr. A. Alcock on Indian Bathyhial Fishes. 361 



ovum had begun. The nucleus, in sliort, with the clear 

 protoplasm that surrounds it, forms a germinal disk lying 

 upon but quite separate from the jolk, as has already been 

 observed in many other Teleostean ova, and as has been 

 commented upon by Mr. E. E. Prince in a paper upon 

 " The Significance of the Yolk in the Eggs of Osseous 

 Fishes '' (Aim. & Mag. Nat. Hist., July 1887, pp. 1-8, pi. ii.), 

 in which will be found numerous references to the work of 

 previous observers. 



In general external form Xenodermichthys Guentheri is not 

 at all unlike Xenodermichthi/s socialis, Vaillant (Exped. Sci. 

 du ' Travailleur ' et du 'Talisman,' Poiss. pp. 162-165, 

 pi. xiii. fig. 1). Its form, too, strongly reminds one of certain 

 t^ternoptychoid types, e. g. Go7iostoma, and even more, as 

 Dr. Giinther has already remarked of the type of this genus, 

 of some of the Stomiatidaj. 



The details of its internal (visceral) structure repeat 

 remarkably what I have myself observed in several Alepo- 

 cephaloids, namely Alepocepkalus, Bathytroctes, and Narcetes. 



Leptodekma, Vaillant. 



21. Leptoderma macrojps^ Vaillant. 



Leptodet'ma macrops, Vaillant, Exp6d. Sci. du * Travailleur ' et du 

 * Talisman,' Poiss. p. 166, pi. xiii. tig. 2. 



A magnificent quite perfect specimen, 8| inches long, from 

 Station 134, 753 fathoms. 



Over the intensely black cutis there stretches, from the tip 

 of the snout to the tip of the tail and investing all the fins, a 

 thick velvety opaline-grey epidermis, which much resembles 

 that covering the head of Aulastomatoinorpha (Ann. & Mag. 

 Nat. Hist,, Oct. 1890, p. 307, and Jan. 1891, p. 10). It 

 appears probable that this epidermis is luminous in function, 

 for when the fish was removed, freshly dead, from the trawl, 

 and put into a pail of muddy sea-water under shade, its form 

 could be distinctly made out glimmering, ghost- like, at the 

 bottom of the pail. In the fresh state the epidermis is freely 

 movable over the black skin beneath, but in spirit it contracts 

 and becomes firmly adherent to the underlying tissues. 

 Examined under the microscope nothing further can be seen 

 than branched black and reddish-yellow pigment-cells. 



There is a distinct lateral line, consisting of a single row 

 of large pores, extending from the occiput to the base of the 

 caudal. 



The attenuated caudal is forked. 

 Ann. cD Mag. N. Hist. Ser. 6. Vol. x. 25 



