FISHES—GASTEROSTEIDAE—GASTEROSTEUS INTERMEDIUM. 
89 
berry. Others from Shoalwater Bay, Washington Territory, collected by Dr. J. G. Cooper, 
exhibit no difference in structure from the one just alluded to. 
List of specimens. 
Catalogue number. 
Corresponding No. 
of 
No. of specimens. 
Sex and age. 
Locality. 
13 
0 
r0 
Whence obtained. 
Original number. 
Nature of specimens. 
Collected by— 
334 
1 
Adt. 
Bay of San Francisco_ 
1856 
Lt. R. S. Williamson_ 
Alcoholic. 
Dr. Newberry _ __ 
335 
4 
do. 
Shoalwater Bay, W. T_ 
1853 
Gov. I. I. Stevens_ 
Dr. Cooper_ 
3. GASTEROSTEUS INTERMEDIUS, Grd. 
Spec. Char. —Body plated all over ; peduncle of the tail keeled. Dorsal spines three, moderate in development and incon¬ 
spicuously serrated upon their edges ; anterior one inserted immediately behind the base of pectorals. Insertion of ventrals 
under the second dorsal spine, their own spine being serrated upon both edges, more conspicuously above than below, and 
their extremities not extending as far as the tips of the ossa innominata. Posterior margin of caudal fin concave. 
Syn. —Gasterosteus intermedius, Grd. Proc. Acad. Nat. Sc. Philad. VIII, 1856, 135. 
But we have received from Cape Flattery specimens of this genus which hear, mayhap, a still 
closer affinity towards G. plebeius than even G. serratus. With the latter it agrees in having 
the sides of the body plated all over, whilst it differs by the proportional size of the head, the 
eye, and the spines, both dorsal and ventral. 
Their size is a little over two inches, agreeing in that respect with G. serratus , but the head 
is contained three times and a half only in the total length, in other words, constituting the 
two-sevenths of the latter, and thus resembling more G. plebeius. The upper surface of the 
head is corrugated or granular, and the opercular, as well as the sub-orbital bones, exhibit con¬ 
spicuous series of granulated ridges. The nostrils are nearer the anterior rim of the orbit than 
to the extremity of the snout. The eyes are circular and well developed, their diameter entering 
four times in the length of the sides of the head, and a little more than once in advance of their 
anterior rim. 
The dorsal spines are intermediate in development between those of G. plebeius and G. serra¬ 
tus; their edges are rather inconspicuously serrated. The anterior one is inserted on a vertical 
line passing immediately behind the base of the pectorals, and when bent horizontally backwards 
it reaches the base of the second spine. The latter, when in a similar position, will not extend to 
the third and small spine in advance of the soft fin. The origin of the latter or second dorsal 
takes place in advance of the ossa innominata; its structure, as well as that of the anal, presents 
nothing peculiarly distinct from the same fins in G. serratus, except that the middle rays are not 
quite as deeply bifurcated. The caudal constitutes nearly the eighth of the total length ; it is 
posteriorly concave, and constructed as in the preceding species. The ventrals are inserted 
under the second dorsal spine, and when bent backwards their extremities do not extend as far 
as the tips of the ossa innominata. 
The formula of the rays does not differ from that of G. serratus. 
D I, I, I, 11; A I, 9 ; C 5, 1, 5, 5, 1, 4 ; V I, 1; P 10. 
