49, ZOOLOGY. 
ALOSA MUSICA, Girard. 
Pruatrr XXXI, Figs. 1—4. 
Spec. cHAR. Body subfusiform, elongated, compressed, and tapering posteriorly. Origin of 
ventrals opposite the middle region of dorsal. Posterior extremity of upper maxillary reaching 
the vertical of anterior rim of pupil. Lower jaw longest. Back bluish; sides silvery. A 
series from nine to eleven roundish spots along the sides. 
Syn. Alosa musica, Grp. Proc. Acad. Nat. Se. Philad. VII, 1854, 199. 
Dsscr. The body is elongated, subfusiform in its profile, tapering considerably on the 
peduncle of the tail. The greatest depth, measured immediately in advance of the anterior 
margin of the dorsal fin, is a little less than the fifth of the entire length, whilst the least depth, 
near the base of the caudal, is about the third of the former. The greatest thickness, on the 
thoracic region, is equal to half the greatest depth. The dorsal and abdominal outlines are 
very regular and but moderately convex. The head, which forms about the fourth of the total 
length, continues uniformly towards the outlines just mentioned, in the shape of an acute 
triangle, rounded upon its summit, where the mouth opens, with a lower jaw somewhat longer 
than the upper ; the latter is but slightly notched. Its upper surface is flattened. The upper 
maxillary is broadly dilated, and rounded posteriorly, where it reaches a vertical line which 
would intersect the anterior rim of the pupil. The nostrils are small, and nearer to the tip of 
upper jaw than to the anterior rim of the eye. The anterior one is rounded, whilst the poste- 
rior one is subcrescentic and convex posteriorly. The eye is large and circular, and approxi- 
mates the upper profile of the head; its diameter being contained about four times and a half 
in the length of the side of the head. The opercular apparatus is posteriorly subtruncated and 
undulated ; the upper part of the opercle exhibits small, radiating grooves, whilst oblique and 
rectilinear striz are observed along the anterior half of its lower part. The other opercular 
pieces are smooth. The branchiostegals, six in number, are very thin and flattened; the inner- 
most is particularly expanded and notched upon its posterior and external margin, correspond- 
ing to a similar emargination of the inferior edge of the opercular apparatus at the junction of 
the sub and interopercles. 
The anterior margin of the dorsal fin is nearer to the tip of snout than to the base of caudal 
fin. It is higher anteriorly than long, with its first three rays rudimentary and simple, like 
the fourth, which is the highest; the posterior margin of that fin is comparatively low, having 
but the third of the height of the anterior margin. Its upper margin is concave. The central 
rays are bifurcated twice, the first subdivision taking place upon the posterior third of their 
length. The anal is situated far back, is very low, and subconcave exteriorly ; its base is a 
little longer than that of the dorsal, and its anterior margin less deep than half the height of 
the anterior margin of the dorsal. The second, third, and fourth rays are the longest, and 
remain simple, as well as the first. The central rays subdivide but once. The caudal fin is 
deeply forked, and its lobes are acute, constituting about the sixth of the total length, its cen- 
tral rays bifureating three times upon their length. The origin of the ventrals is situated 
opposite the middle of length of dorsal. These fins are of moderate development, and poste- 
riorly subtruncated, their tips projecting slightly beyond the longest rays of the dorsal. The 
pectorals are well developed, of a rather slender appearance when contracted, and very broad 
exteriorly when expanded. They are inserted immediately beneath the subopercle; their 
external margin is twice and a half as long as the internal, their posterior edge being rounded 
and subconcave. The central rays bifurcate three times, as do also those of the ventral fins. 
By. Viv DAG ATS PLS Oe 9.8. Teds Vv 82 eet 
The anterior ray of both ventral and pectoral fins is simple, but articulated. 
