156 



December 1, 1861. 



> President in the Chair. 



Dr. Ayres presented the following description of a new ichthjic 

 form, from the coast of Lower California. 



Cynoscion parvipinnis, (Ayres.) 



Form elongated, somewhat compressed, head pouited, dorsal out- 

 line more arched than the abdominal. Length of the head one- 

 fourth of the total length ; greatest depth a httle less than one-fifth 

 of the length. Lower jaw longer than the upper. Mouth of moderate 

 dimensions, the maxillary scarcely reaching a hne even with the 

 posterior border of the orbit. Teeth very small on the sides of the 

 upper jaw, becommg larger anteriorly, while in front are two or three 

 quite large canines ; those on the sides of the lower jaw are larger than 

 those of the upper, decreasing in size toward the front. Eye distant 

 not quite twice its own length from the anterior border of the upper 

 jaw, its length being contamed a httle over sLx times m the length 

 of the head. Scales soft, covermg the entire body and the head 

 except the jaAvs. 



The origin of the first dorsal fin is a little posterior to the line of 

 the tip of the operculum ; its height at the third spme, which is the 

 highest, is about half the depth of the fish ; the last two spines are 

 very short and almost concealed, causing the fin to appear as though 

 se})arated by quite an interval from the second dorsal, though it is 

 in fact continued to it. Its length is more than twice its height. 



The second dorsal is liighest at the first soft ray, (which is pre- 

 ceded by a short spinous one,) and diminishes thence regularly. Its 

 gi'eatest height, which is contained three times in its length, is a 

 little less than that of the first dorsal. 



The pectorals are somewhat pointed, theii' height less than one- 

 umth of the length of the £sh. 



The ventrals, arising posterior to the origin of the pectorals, have 

 a height equal to half the length of the head. 



The anal a little posterior to the hne of the middle of the second 

 dorsal. Like that fin, it is highest at the first soft ray, (which is 

 preceded by a short spinous one,) and diminishes thence regularly. 

 Its length and height, which are equal, are equal to the height of 

 the second dorsal. 



The caudal fin is even posteriorly ; the height of the outer rays 

 is about half the length of the second dorsal. 



D. X ; 1-22 ; P. 10 ; V. 1-5 ; A. I-IO ; C. 4-1-8-7-1-3. 



