JOHN DORY. 
307 
easily recognisable, especially when the black, lateral 
spot is still to be found. Its recognition is also facilitated 
considerably by the long appendages of the fin-mem- 
brane of the first dorsal fin and the great length of the 
ventral fins". On closer examination, however, the head* 
is the most striking point, for with the eyes set high 
and rather far back, though by no means small 0 , it re- 
minds us somewhat of that of a pig. It is most 
singular in appearance when the mouth is protruded. 
The nasal (frontal) processes of the intermaxillary bones 
are so long that their point, when they are drawn back, 
i. e. when the mouth is closed, extends up to the fore- 
head between the eyes' 7 , where, on the top of the head, 
they slide in a groove extending along the whole length 
of the frontal bones, which is somewhat broader at the 
beginning and end, and the margins of which end 
in the above-mentioned spines, which really belong to 
the frontal bones, but are situated as though they were 
occipital spines. The great length of the nasal processes 
of the intermaxillary bones enables the fish to protrude 
the mouth so far that the snout, which is then extended 
in a lateral direction as well, becomes considerably 
larger than the rest of the head. The flat maxillary 
bones 0 then turn in their articulation, which is covered 
by the front part of the preorbital bone, and assume a. 
vertically downward or forward position. By this ac- 
tion everything immediately in front of the fish is 
sucked into the mouth, and when the latter is again 
closed, the capture may be no small one. The lower 
jaw' always projects beyond the upper, but when the 
mouth is closed, the difference is less apparent. 
The two nostrils on each side are set close to the 
anterior orbital margin, being mutually separated only 
by a narrow dermal wall. The anterior is the smaller 
and almost round, the posterior being oblong and 
perpendicular. 
The base of the spinous-rayed dorsal fin is about 
equal in length to that of the soft-rayed, which, on the 
other hand, is somewhat longer and higher than the 
soft anal fin, to which it is analogous in other respects. 
Both the latter fins are rounded at the margin and have 
the longest rays in the posterior half, the longest ray 
in the soft dorsal fin being about half as long as the 
caudal fin. The margin of the caudal fin is also slightly 
rounded (convex), the outer branched rays being, how- 
ever, slightly longer than the middle ones. Its relative 
length 9 diminishes with increasing age. The pectoral 
fins are small* and rounded, with few rays, and situat- 
ed below the middle of the sides and behind the 
perpendicular from the insertion of the ventral fins. 
Their length in young specimens is more than half 
that of the lower jaw, but in older ones equal to or, 
eventually, less than this measurement. 
The lateral line forms a sloping curve from the 
temporal region to the middle of the side, just in front 
of the perpendicular from the middle of the base of 
the soft-rayed dorsal fin, from which point it runs 
in a straight line to the middle of the base of the 
caudal fin. 
The Dory attains a length of about 5 dm., accord- 
ing to Couch, 6 dm., according to Moreau. Its ma- 
ximum weight on the English coast, according to the 
former writer, is about 8 kgrm. As we may easily 
see by the shape of the fish, it can scarcely be regarded 
as possessing any great power of swimming. The dee}) 
body may indeed be steered and maintained in an upright 
position by the help of the long ventral tins and the 
high, spinous-rayed dorsal fin with its long, dermal 
° The relative length of the ventral fins decreases during growth from 38 % of the length of the body, in the youngest of our spe- 
cimens, to 2 0 1 / 2 , in the oldest specimen. 
b The relative length of the head, measured from the anterior margin of the articulation of the maxillary bones to the end of the 
opercular flap, apparently undergoes but slight change of growth, varying in our specimens between 29 and 31 % (29‘1 — 30'9) of the length 
of the body. 
c The longitudinal diameter of the e}'e varies with age, in our specimens, between 9 and about 8 % (9'1 — 8'2) of the length of the 
body or 30 and 27 % (30'5 — 27’3) of the length of the head. 
d The distance from the middle of the anterior margin of the intermaxillary bones to the tip of their nasal processes is about equal 
to (sometimes somewhat less than) the length of the maxillary bones or of the interoperculum, equal to the distance from the anterior margin 
of the preorbital bone to the hind margin of the preoperculum, twice the longitudinal diameter of the orbit, or half the depth of the body 
at the beginning of the soft-rayed dorsal fin; but in young specimens somewhat less than the last measurement. 
e The length of the maxillary bones varies in different individuals between about 19 and 2 0 1 / •-> % (19*1 — 20'4) of the length of the 
body. They are flat even above the articulation and the upper (anterior) end is as broad as the lower, but at the articulation they are narrowed. 
f The length of the lower jaw, including the angular spine, varies between 23 and 25 % (23'0 — 24’7) of the length of the body. 
rj In the smallest four of our specimens the length of the middle rays of the caudal fin varies between about 24 and 22 % of that of 
the body. In the largest specimen the caudal fin is damaged, but its length seems to have been scarcely more than 16 / of that of the body. 
h The relative length of the pectoral fins also decreases during growth, in our specimens, from about 13 to 11 / (13'2 — 1 1 ' 2) of 
the length of the body. 
