766 MR FRANK J. COLE 
dorsal surface, near the tip, gave off on both sides a short backwardly projecting hook, 
which then curved upwards and inwards and finally downwards, to be connected by a 
short stout ligament with the lateral labial cartilage just behind where the latter fuses 
with the cartilage of the third tentacle. It certainly appeared to express a tendency 
to, or to be a relic of, a cartilaginous connection between these two elements. The 
cornual cartilage terminates in front opposite the fourth nasal ring. 
F. Nasat Tuse anp CapsuLe. (Figs. 1, 5, and 6.) 
The nasal aperture is a large opening situated terminally on the dorsal surface of 
the head. ‘It is guarded laterally by two short, poimted tentacles on each side—the 
nasal ‘‘ barbels”—and dorsally by a truncated lip. I am not able to follow W. K. 
PaRKER in distinguishing “three nasal barbels on one side, and four on the other.” * 
This external opening leads into a long dorsal tube (n. ¢b.), which in a 454 cm. Hag 
measured 14mm. ‘The latter, in its turn, passes first into the olfactory chamber and 
then into the hypophysial duct or naso-palatine canal. As in Bdellostoma, according 
to J. MULuer and Ayers and Jackson, the nasal tube is widest in front, and gradually 
tapers as it approaches the olfactory capsule (n. c.). ParKER, however, figures it as 
being much narrower anteriorly. It is remarkable in the myxinoids on account of 
its strong superficial resemblance to a trachea, and it is supported at intervals by 
cartilaginous rings, which are, however, imperfect ventrally. In some sections of a 6°5 
cm. Hag, lent me by Dr Brarp, the nasal rings so closely approximated in the 
mid-ventral line as to be almost in contact, whilst in another series of a 25 cm. Hag 
the posterior rings overlapped. The number and form of these rings are subject to 
variation (cp. figs. 1 and 6). In the specimen and in the series above, there were 
eleven in both cases. PARKER also describes and figures the same number, but, as he 
failed to find the first one, his total should be twelve. Ayers and JAcKSON state that 
there are normally nine in Bdellostoma, with occasional variations of cight and ten. 
J. MGLLER gives ten for Bdellostoma, and ParKER distinguishes twelve. The latter 
author figures all these arches in Myaine as independent ; but, as shown in figs. 1 and 6, 
about the first and last three are usually connected up, the last being further fused at 
intervals with the anterior transverse bar of the olfactory capsule. These connections 
I have found both in dissections and in serial sections. As, however, stated by AyERs 
and Jackson for Bdellostoma, “the nasal arches are found to vary to a considerable 
extent in number, form, and size, both relative and absolute.” t 
The first nasal ving (1) is situated at the anterior edge of the dorsal lip of the 
external aperture. It is connected dorsally with the second ring by a backward median 
process (fig. 5). These parts, as well as the dorsal portions of the other nasal rings, can 
be seen in the living fish showing through the skin. In the neighbourhood of the 
median process there projects, downwards and forwards into the cavity of the tube, a 
* Op. cit., p. 386. t+ Op. cit., p. 199. 
