78 



CALIFORNIA ACADEMY OF SCIENCES 



Table of gill-rakers and plates of straight part of lateral line. 



142. Caranx caballus {Gmitliar). 



Frequently appearing in considerable numbers; seven specimens preserved. 

 These, in addition to three specimens from Mazatlan, have been compared with four 

 specimens of G. crysos from the Atlantic (two from Jamaica; one from Woods Hole, 

 Mass.; one from Florida). 



C. cahallus seems to be more slender, the depth varying from 3] to 3| (3 to 

 3| in C. crysos). The former has two or three of the plates on the caudal peduncle 

 lengthened antero-posteriorly. Counting from a point opposite the base of tlie last 

 dorsal ray to opposite the beginning of the short outer rays of the caudal, they num- 

 ber four or five in C. cahallus, and seven or eight in C. crysos. 



The two species do not differ in length of the pectoral or in the number of 

 plates in the straight part of the lateral line, as has been alleged. In both, the 

 pectoral varies from 2| to 3|- in the length, and the plates from 47 to 50. 



143. Caranx marginatus Gill. 



Common in the Panama market. We supplement the description given by 

 Jordan and Evermann (1896, p. 922) as follows: 



Head from 3i to 3{ in length; depth 2'\- to 3. Dorsal in four specimens 

 VHI-I, 21; in two specimens VIII-I, 20. Anal in four specimens II-I, 16; in two 

 specimens II-I, 17. Eye (iris) 4 to 4|- in head; maxillary 3 to 35, reaching to below 

 posterior border of pupil. The gill-rakers number 4 or 5 + 14 or 15. Pectoral 2f 

 to 3 in body. Arch of lateral line 1| to If in its straight portion. Plates in straight 

 part of lateral line in two specimens 30, in three specimens 31, in one specimen 32. 



We have specimens in the collection of Stanford University from Mazatlan, 

 Socorro Island and the Galapagos Islands, which agree with our Panama specimens 

 in all respects. 



Doubtless all of the records of the occurrence of G. latus in the Pacific are 

 referable to either G. marginatus or G. medusicola. G. marginatus differs from G. 

 medusicola and G. latus in having a slenderer form, and fewer plates in the lateral 

 line. 



We have re-examined the two type s^iecimens of G. medusicola from Mazatlan, 

 and also several specimens from Clarion Island. None of them exceed 7 inches in 

 length. From G. latus of the same size (of which we have specimens from Key 

 West, St. Lucia and Bahia, Brazil), G. medusicola differs in the following respects: 



* GiU-Kikers given for lower arch ouly; the rudiments enumerateLl separately iu each case. 



