134 ZOOLOGY OF THE 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 arouata. 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. 

 Colours. — " 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 con- 

 dition, 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 serratures 

 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 opercle very much as in the Pilchard, but the interopercle more developed. The 

 posterior margin of the opercle and subopercle taken together is almost quite straight, without 

 any emargination anywhere, and not far out of a vertical ; the subopercle is cut nearly square 

 at bottom. The preopercle is much veined : there are also some veins on the upper part of 

 * In the pilchard it is one-fifth. 



