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Show 134 .ZOOLOGY OF TilE VOYAGE OF THE BEAGLE. differs also from the Herring in having the ventrals exactly in a line with the commencement of the dorsal, this last being placed a little further back than in that species. D. 18; A. 19; C. 19, &c.; P. 18; V . . 8. Length 3 inches. " Caught at night, off Cape Ines, Tierra del Fuego, two miles from the shore, in thirteen fathoms."-D.-The specimen is probably not full-sized, 2. CLUPEA ARCUATA. Jen. The present species is from Bahia Blanca. The specimens, of which there are two, are also in bad condition like the last, and probably not full-sized. FoRM.-Body deep, with the ventral line swelling rather more outwards than the dorsal. Greatest depth a little exceeding one-fourth of the entire length. Very much compressed: abdomen carinated, and very sharply serrated, the serratures sharper than in the common sprat. A few minute teeth at the extremity of the lower jaw, and also on each side of the intermaxillary, near its junction with the maxillary; the lower half of this last finely serrated. Pieces of the gill-cover much as in the Sprat ; the subopercle rounded at bottom, the opercle with a shallow notch near the upper angle. The dorsal commences exactly in the middle of the entire length, excluding caudal. The ventrals are as nearly as possible directly beneath its first ray : these fins are very small, and shorter than in the sprat. D. 18; A. 23; C. 19, &c.; P. 16; V. 7. Length 4 inches 2 lines. CotouRB. -"Back blue; belly silvery."-D. The second specimen is similar, only smaller. Both were taken in the month of September. 3. CLUPEA SAGAX. Jen. A third species of Clupea, in Mr. Darwin's collection, likewise in bad condition, much resembles in general form the common Pilchard. Depth the same as in the Pilchard, but the head larger and longer than in that species, being one-fourth* of the entire length. Abdomen smoother; no appearance of any scrratures in front of the ventrals. Lower jaw but little advanced beyond the upper. No perceptible teeth, more than a few very minute serratures near the lower extremity of the maxillary. Diameter of the eye about one-fifth the length of the head. The form and veinings of the pieces.of the o~ercle very much as in the Pilchard, but the interopercle more developed. The postenor margm of the opercle and subopercle taken together is almost quite straight, without any emargina.tion anywhere, and not far out of a vertical ; the subopercle is cut nearly square at bottom. The preopercle ie much veined : there are also some veins on the upper part of 111 In the pilchard it is one-fifth. |