FISHES OF CEARA, BRAZIL JORDAN AND BRANNER I5 



The tvpe (No. 4, Rocha Collection) is 85^ inches long, fairly well 

 preserved from the preopercle backward, and represented in counter- 

 part in a nodule of coarse sandstone. 



The species may be known from the Elopidse found at Ceara, by 

 the narrow scales, by the subheterocercal tail, and by the large 

 opercle, which is many times larger than the horizontal subopercle. 

 This small subopercle separates this from other species of Lepto- 

 lepida^. From the Cretaceous species of Elopidse it is distinguished 

 by the insertion of the ventrals under or slightly before the front of 

 the dorsal. This is seen also in the genus Ccaraiia, but in that genus 

 both dorsal and ventrals are inserted farther back. 



A second specimen (No. 3, Rocha Collection), also in counterpart, 

 9^/^ inches long, shows the thin rhomboid scales and the fins fairly 

 well, but the head is entirely crushed. 



Another nodule (No. i, Rocha Collection) is referred provision- 

 ally to Tharrhias araripis, with which it agrees in general form, in 

 the insertion of the ventrals directly below the dorsal, and in having 

 the distance from dorsal to gill opening about equal to depth of body. 

 The bones of the head are all crushed, and the thin scales, about 

 equal in number to those of Tiiarrliias araripis. are not any of them 

 enameled nor rhombic in form ; but, on the other hand, none of them 

 are well preserved. The vertebrae are well preserved and compactly 

 inserted. There is no trace of lateral line. We do not much doubt 

 the identity of this specimen with the type of Tharrhias araripis, but 

 the difference in the scales suggests that possibly the rhombic form 

 in the latter case may be due in part to shrivelling of the specimen 

 before it was encased in clay. Of these specimens. No. 3 is in the 

 U. S. National Museum and the counterpart of No. i in the geo- 

 logical collection of Stanford University. 



Family ELOPID.E 



The family of Elopidse is characterized among the soft-rayed 

 fishes by the presence of a triangular bone, or gular plate, between 

 the rami of the lower jaw. This plate is present in the Amiatidae 

 and in some other ganoids, and it furnishes strong evidence that the 

 Elopidse are descended from extinct forms resembling Amiatus. In 

 any event, the Elopidse are among the oldest and most generalized of 

 all the bony fishes. Their occurrence at Ceara in company with 

 extinct ganoids like Bclonostouius and Lepidolepis is significant. 

 Another character of the Elopidse is the enlargement of three bones 

 of the suborbital ring below and behind the eye, a character which 

 appears in others of the lower Isospondyli and points to their ganoid 

 origin. 



