121. 
narrow band onthe jaws, (no enlarged teeth being developed at the 
extremity of the mandible,) and the tail with an eradiate membrane 
under its terminal portion. 
Gastrostomus Bairdi. 
The question must hereafter arise whether the fishes examined by 
M. Vaillant and ourselves are the same or really distinct generic 
types. Little value is to be attached to the relative extension (within 
the limits observed) of the jaws, but the proportions of the cranium 
(if confirmed) would indicate that the two forms exhibit marked diffe- 
rences, and our respect for the eminent French naturalist will not per- 
mit us to assume error on his part in reference thereto, and, conse- 
quently, we propose (provisionally at least) to differentiate the two 
forms as distinct genera. There is no a priori reason why there should 
not be two or even many genera of the Lyomerous type, and the dis- 
covery of three very distinct generic modifications of the Nemichthyoid 
eels in addition to the already described species, by the »Albatross«, 
shows what revelations may be still expected from deep-sea explorations. 
No less than three new family types (including the Eurypharyngids) 
and 20 new generic or subgeneric forms, nearly a third more than have 
been described by Dr. Günther, as deep-sea fishes, from the 
collections of the »Challenger« made in three years, were obtained by 
the »Albatross« during the past season. 
The further anatomical details exhibited by the Eurypharyngids 
are most remarkable. The parallelism and opposability, of the upper 
jaws, upon each other when closed, is nowhere else seen among fishes 
and equally unique is the divergence of the neurapophyses and 
the closure of the neural canal above simply by a membranous roof or 
sheath supported by the divergent apophyses. (The inclosure is a 
wide serous space which extends into the cranium, expanding so that 
the space around the brain is as capacious relatively as, or more so than, 
in Elasmobranchs. The cranium in front is cartilaginous and no nasal 
or vomerine bones are developed. For other data, we must refer to a 
memoir »on the anatomy and relations of the Eurypharyngidaet to 
be soon published in the »Proceedings of the U.S. National Museumc. 
A few words are meanwhile demanded as to the morphology and rela- 
tions of this type. È 
Mr. Vaillant considers the dentigerous bones of the »upper jaw« 
to be »free intermaxillaries«, and that therefore vit would be the Scope- 
lidae that Burypharynz would approach, especially as it does not pre- 
sent the hyoidean barbel which has hitherto been indicated as character- 
istic of the Stomiatidae. However, of all fishes it is to Malacosteus 
niger, Ayres, placed in the latter family by zoologists, that we are 
