136 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
cartilage (Pl. IX, fig. 1, an.) and its paired cornual append- 
age (v.e.); and at first sight the more numerous and delicate 
structures met with in the Hags, present nothing in 
common with these, except for their approximate arrange- 
ment in an annular series. 
Returning now to Callorhynchus (in which, as already 
seen, [ante. p. 131] a considerable lip akin to the Lamprey’s 
suctorial one 1s developed), no inconsiderable similarity 
suggests itself, on comparing its labial cartilages with the 
structures which in the Lamprey and Hag appear so 
entirely different. The labials of Callorhynchus (Pl. X, 
fig. 5) are usually nine in number on either side. The lead- 
ing one (Jb. ix), which is so immense as to be little short of 
the mandible in functional importance, suggests that of the 
Hag (lb. iv, fig. 2) but for its complete confluence with its 
fellow in the mid ventral line ;* in respect to this, and 
to the extent to which it supports the lip, it no less 
obviously recalls the lower half of the Lamprey’s annulus, 
while its prolongation downwards and backwards among 
the sub-dermal tissues suggests that it at least functionally 
represents the cornual appendages of that also. Among 
those cartilages which remain, the inwardly directed 
element (/b. v) suggests, in a similar manner, the base of 
the T' shaped piece of Bdellostoma, which may be distinct ; 
both he above the mouth, and they differ most conspicu- 
ously in the fact that whereas that of the Hag stops short 
of the olfactory region, that of the Chimeroid reaches it. 
Chief among the remaining pieces in the Hag are six 
(the ‘‘ basihyals’”’ of Parker) all lying closely approximate 
to each other and to the great antero-ventral cartilage 
(av. fig. 2), the series forming a kind of bed for the expanded 
tooth-bearing ‘‘tongue.”’ The two posterior of these (c7.) 
*On examination of a young Callorhynchus of 130 mm. total length I 
find this to be represented by two distinct cartilages as in the Hag. 
