ACADEMY OF NATURAL SCIENCES. 93 



These butterflies not having 1 a very powerful flight are generally confined to 

 circumscribed localities, in which they are generally plentiful and easily collected. 

 Their caterpillars are frequently social like those of the Vanessae, preferring the 

 family of Scrophalarineous plants, (Scrophularia in California, Linaria and 

 Veronica in Europe), but inclined more to polyphagy than the Argynnides, in 

 their predilection for the Yiolarineae. Besides the Scrophalarineae the Melituae 

 live on Plantago, Lonicera, Scabiosa, and some even are found on shrubby trees 

 of Salix, Populus, and Fagus. 



Dr. Cooper presented a continuation of his descriptions of fishes : 



On new Genera and Species of Californian Fishes— No. II. 



by j. g. cooper, m. d. 

 Exoccetus, Artedi. 



E. Californicds, Cooper, Californian Flying-Fish, State collection, species 



1012. [Fig. 20.] 

 Specific characters. — Height of body one eighth of its length from tip of 

 nose to fork of tail, length of head almost one fifth of the same (0-19). Width 

 of forehead in front of eyes more than five eighths the length of head (0-G9) ; 

 diameter of eye less than one third of same length (0-30). Scale between 

 eyes equilateral, and a little less than half of the width of head. No granulated 

 area in front of orbit, and but a very narrow one behind it. Preoperculum 

 rounded rectangular. Pectoral fin extending to halfway between end of dorsal 

 and base of caudal, - 60 of total length. Ventrals inserted nearer operculum 

 than base of caudal, and extending to middle of anal. Dorsal commencing 

 over 36th scale and extending to 48th. 



D. 12, P. 14, V. 6, A. 10, C. 3-1-4-5-1-6. Scales 58 ^. 



Colors. — Steel-blue, fins smoky, below silvery, iris gilt. 



General form much elongated, subcylindrical. Top of head perfectly flat, 

 its width equal to its depth. Anterior half of body nearly as broad as high, 

 compressed above. Posterior half compressed laterally, tapering to tail, the 

 caudal peduncle three times as high as it is broad. A slight ridge along inser- 

 tion of dorsal. Lateral line prominent, running close to insertion of ventrals. 

 Proportions of fins to total length, as follows : 



Length of dorsal 011 



Height of ventrals 0-23 



Length of anal O07 



Length of caudal, upper lobe 0-15 



Length of caudal, lower lobe 0-22 



Height of pectoral '. G"60 



Length of specimen fifteen inches, the figure representing it half the natural 

 size. One specimen obtained at Catalina Island. 



Eemarks. — In the preceding diagnosis I have followed the arrangement of 

 specific characters adopted by Gill in his description of two new species of 

 Exoccetus from the Pacific Coast of Central America. (Proc. Acad. Phil., 



