Jordan : Fossil Fishes from Riacho Doce. 33 



Our species, from the Eocene, seems somewhat different from Chiromys- 

 tiis ma-ii'soni Cope, and we gi\-e it the name of Chiromystus alagoensis. 



The type, Number lOO, with its duphcate, Number lo6, represents the 

 jaws and part of the skull, with other crushed structures, the broad and 

 strong pectoral fins being attached. The first ray of the pectoral is very 

 broad and flat, and there are five other rays well defined, with traces of 

 two or three more. The membranes connecting the first three rays are 

 represented and are distinctly striate. The mouth is very large, with a 

 long, curved maxillary, e.xtending to the articulation of the lower jaw 

 and extending far beyond the point where the eye seems to have been 

 located. In the front of the maxillary are moderate teeth. The jaws 

 are subequal,. the cleft of the mouth oblique, the lower jaw very heavy, 

 with a prominent lateral ridge and a longitudinal depression below. There 

 are a number of moderate, subequal teeth preserved. 



Number ii6 (Plate IX, fig. 15), with its duplicate, Number 117, 

 represent the pelvis of a fish, with two ventral fins, each with about six 

 broad, articulated rays, the first two or three very wide, and all much 

 branched towards their tips. As these fins are about an inch long, they 

 must have belonged to a large fish, certainly the same as number 100, and 

 probably to the same species as number 114 also. 



According to Woodward, the ventral fins in Chiromystus mawsoni are 

 very small. If C alagoensis is also a Chiromystus the size of these fins 

 will indicate a specific difference. The form of the jaws in this fish agrees 

 very fairly with Allport's figure (Quart. Journ. Geol., XVI, i860, PI. XIV, 



fig- 4)- 



Collector's Number 114 (Plate XIII) and its duplicate, Number 115, 

 represent the posterior part of a long vertebral column, containing 30 

 vertebrae and indicating that the total number must have been 50 or 60. 

 The vertebrae are about as long as deep, double concave, each posteriorly, 

 with three coarse ridges on each side between these two deep, longitu- 

 dinally extended pits. The caudal fin is slender, the lower half preserved, 

 apparently deeply forked, the anterior rays springing from the last fiv'e 

 of the vertebrae. The caudal seems to have been deeply forked, and 

 sharp at tips, the rays stout at base and jointed. There are traces of a 

 long anal fin, with here and there a ray preserved, and in the surface of 

 the specimen there are traces of what may have been small cycloid scales, 

 but possibly only fragments of skin. 



Number 202 is a part of the vertebral column of a smaller example 

 of the same species, but in such bad condition as to show nothing. The 



