rilOLI])OPIIOIlUS GREGAlllUS, Sj). 710V. 
Plate Yl, Pigs. G-10. 
Obs . — The small fishes of this species arc among the commonest of 
the ITawkcshiny fossils, and seemed to have lived and died in considerable 
shoals. About seven specimens may he selected to elucidate all the main 
points in their structure, except the osteology of the skull, of which little 
can he discerned. 
(g) The type-specimen, the trunk being preserved in counterjiart. 
This is shown of twice the natural size in PI. VI, Pig. 6, and 
is associated on the same slab with two smaller examples. 
(b) A more incomplete smaller specimen, shown of twice the 
natural size iu PI. VI, Pig. 7. 
(c) A still smaller, more elongated fish, shown of twice the natural 
size in PI. VI, Pig. 8. 
{(I) Head and anterior portion of trunk. 
(c) Imperfect head and anterior portion of trunk, the head being 
shown of twice the natural size in PI. VI, Pig. 10. 
(/) A small elongated fish, wanting the fins; the head shown of 
twice the natural size in PI. VI, Pig. 9. 
{(/) Pour associated small lishes upon one slab, with a small 
'Dictyopyge. 
General Form . — As shown by the figures, there is considerable 
variation in the proportions of the individuals assigned to this species ; but 
it docs not appear possible to discover any characters by which they can be 
further separated. The original of Pig. 8 is much smaller and more elongate 
than the type, but is partly connected with it by No. b (Pig. 7) ; and in two 
instances these forms are associated upon one slab of rock, as if they formed 
part of the same shoal. It may also be noted that in the original of Pig. 8 
the dorsal and anal fins are depressed, while there are signs of post-mortem 
compression; and an individual equally slender, upon the slab No. g, 
exhibits the tail as widely spread as that of the type. The head, with the 
opercular apparatus, does not occupy more than about one-fifth of the total 
length of the fish ; the fin-rays are robust, and, in the median fins, spaced 
considerably apart; and the dorsal fin is large, arising opposite the space 
between the pelvic pair and the anal, and partly opposed to the latter. 
