Artuur.—On the Picton Herring. 209 
at posterior end, which reaches slightly beyond vertical line drawn from 
anterior margin of orbit. Mandible projects a little beyond intermaxil- 
lary. Mouth, when fully open, has a gape of three-quarters to an inch. 
Opercula all well defined, posterior margin nearly vertical.and straight, five 
or six distinct striæ on preoperculum pointing to base of pectoral fin. Dia- 
meter of eye one-fifth length of head, pupil black, iris olive-yellow. This 
organ—the eye—is sunk with orbit about one-eighth of an inch (or below 
the plane of the cheek), and is protected by a beautifully-transparent dise 
of apparently thickened skin, convex in form, extending half an inch 
in front of centre of eye and three-tenths of an inch behind the same 
point, and provided with a slit or opening directly over the centre of 
eye vertical in position and gibbous in form or spindle-shaped. This 
dise is evidently meant to protect the eye, and, at the same time, to 
compensate for the diminution in the range of vision caused by the 
eye being sunk in the head. Fins small and delicate in structure, rays 
mostly soft or branched. One dorsal fin only, situated exactly midway 
between snout and origin of middle or shortest rays in tail-fin, fourth 
raylongest. Ventral fin origin, in vertical line from eighth or middle ray 
of dorsal fin; tail-fin deeply forked, nearly bifurcate. The posterior end 
of the anal fin is distinguished by a few long feathered rays much longer 
than those adjoining them in body of fin. The scales are large, irregularly 
rounded, transparent, and on exterior margin pectinate, also very tough, 
and not deciduous. Along the base of or parallel to base of the dorsal, pec- 
toral, and ventral fins, rows of scales are situated differing in form from the 
body-scales of the fish, but resembling in shape those fins beside which they 
grow ; and on each lobe of the caudal fin on both sides are scales or skin- 
like plates, somewhat like the respective lobes they are attached to. The 
other or body scales, besides possessing the shape described above, are - 
arranged in layers which overlap each other so as to leave a diamond pat- 
tern over the surface of the trunk of the fish. As in the pilchard of the 
English channel, described by Yarrell, a series of three-limbed scales, or 
rather dermo-hemal plates or processes (for they are bony) exist along 
the outline of abdomen from the pectoral to the anal fin. These are as 
figured, are buried underneath the true scales, they diminish 
in size towards the tail, overlap each other, and are placed 2n 
with short end of mid portion pointing towards the tail. 
Looked at transversely they conform to the precise outline 
of that part of the hemal arch here situated, viz., the bot- Cp 
tom. No lateral line visible on this specimen. In colour, 
indigo blue on back and head, 
: shading off into grey on sides, and silvery 
white on belly, 
14 
general aspect of body very silvery. There are seven or 
