39 



which is denominated by naturalists the interoperculum, while the 

 upper was in the usual position. 



FAM. CARAXGID.E. 



Most of the species of this family, which is a subdivision of the 

 old mackerel family (Scombridae), that occur upon this coast, are 

 widely spread and well known forms, and the presence of some of 

 them was not suspected until Professor Jordan commenced his 

 researches in the Spring of this year. 



Trachynotus ovatus, a form more nearly allied to the New Orleans 

 Pompino than is the fish which hears that name at San Francisco, 

 was recorded by the writer as from Lower California in 1876, and 

 probably extends as far north as San Diego. 



T. pa/mpanus, also found on the Atlantic coast of North America, 

 occurs in Lower California, but has not yet been met with within 

 the limits of our State. It may readily he known from T. ovatus by 

 its more elongate body, accompanied by longer dorsal and anal tins, 

 and by its darker color. 



Trachwrus saurus, the Horse Mackerel, is an old friend of the 

 Levantines who carry on here the same occupations they pursue in 

 the Mediterranean. Occasionally it strays up the eoasl as tar north 

 as San Francisco. It is taken in large numbers in seines, and salted 

 for bait. It may he known from all other fishes found in the markets 

 of San Francisco by the tow of keeled plates along the center of tie 

 posterior part of the body for its entire length. 



Caranx ail, nil us may be known from the last species by the limita- 

 tion of the keeled plates to the posterior portion of the body, as well 

 as by a black patch upon the operculum. 



Nave rates ductor, the Pilot-fish of authors — that small oceanic fish 

 which is said to guide the shark to his prey — is said to occur south of 

 Point Concepcion. It may readily be distinguished by the darker 

 vertical bands across its bluish Hanks. 



Selene argentea is another species, found both in the Atlantic and 

 Pacific, but at present not known to occur in the waters of our State, 

 although, as it is common in Magdalena Pay, it is not improbable it 

 may straggle farther northward. It is excessively compressed and 

 thin, the top of the head almost vertical, so that it looks highly intel- 

 lectual. The anterior rays of the dorsal and anal are very long. 



Seriola lalandi — This is the well known Yellow-tail of the coasts of 

 the tropics, and South America and Africa. At present, it is on 

 record from this coast only from San Diego and the Coronados Islands 

 northward to Santa Barbara, where it is abundant in the summer, 

 spawning about July and August. In winter it is not seen. It is 

 taken entirely bj r trolling, sometimes in considerable numbers, and 

 as a fresh fish, ranks somewhat below the Barracuda. When dried, 

 it is considered equal to the Barracuda, or to Caulolatilus. 



It feeds upon squid and small fishes, and reaches a weight of fifty 

 to sixty pounds, and a length of four to four and a half feet. 



The curious Remoras, which have a sucking disk of large size 

 occupying the whole of the upper side of the head and nape, consti- 

 tute a small family, nearly related, in some respects, to the CarangidaB 

 and Scomhridae, or mackerel family. 



The sucking disk is a transformed spinous dorsal, and consists of 

 a number (varying according to species) of transverse lamina? united 



