68 PROCEEDIISIGS OF UNITED STATES NATIONAL MUSEUM. [1865. 



NOTES ON SKELETONS OF ETHEOSTOMATINiE. 

 Py DAVID M. JORDAN and <JARI> H. EIOENMAN. 



The juuior author of the present paper has prepared the skeletons of 

 20 species of Mheostomatinw. These have been studied with a view to 

 ascertaining- what skeletal characters, if any, distinguish this group as 

 a whole from the PercUia\, and also in what resi)ects the different sub- 

 ordinate groups or genera are distinguished from each other. 



The studies here made have been, in a measure, superficial, and refer 

 especially to the upjier parts of the cranium and the numbers of the 

 vertebrae. A detailed comparison of the smaller bones, especially those 

 of the lower parts of the head, ofi'ers numerous difficulties, as several 

 of the species examined do not reach a greater length than two inches. 

 The jaws and the membrane bones of the skull, being sufficiently de- 

 scribed elsewhere, are not noticed in this paper. 



1. Percina caprodes, Rat". 



This species is the largest of the Darters, and in the structure of the 

 cranium it is the one which approaches nearest to the typical Perches. 

 In this respect, it is evident that Percina is more nearly allied to the 

 other Darters than it is to Ferca. Its cranium is decidedly more like 

 that of Perca than like that of ^tizostedion. So far as the cranium is 

 concerned, Perca is probably nearer Percina than either is to Stizostedion. 



Comparing the skull of Percina with that of Perca, we hnd that in 

 the former the bones of the skull above are much smoother; the ridges 

 and grooves on the frontal, i)arietal, and mastoid regious, conspicuous 

 in Perca., are nearly obsolete in Percina. The tube-like pores on the 

 frontal bones conspicuous in Perca are barely visible in Percina. Pari- 

 etals and supraoccipital with radiatiug stri;e, more regular than in 

 Perca, the ridges lower and less sharp. Frontal region narrower than in 

 Perca, and less depressed. Supraoccipital bone longer than in Perca, 

 its crest very much smaller, not rising to level of the occiput. Sutures 

 of skull more distinct than in Perca. Skull in profile less convex at 

 occipitt, more elevated between eyes. 



Sui^rascapula in Percina trifurcate, the forks slender, the posterior 

 part without serration ; its form similar to that of Perca. Scapula, L- 

 shaped, thinner and weaker than in Perca ; its edge not serrate. Fora- 

 men of ulna much larger than in Perca. Pelvic bones proportionately 

 shorter and broader than in Perca. Coracoid without serrations. Rest 

 of skeleton essentially as in Perca; number of vertebrje, 33 -f 21 =44. 

 Lower pharyngeals triangular-elliptical, with large teeth. 



As compared with the other Darters, the skull of Percina is much 

 broader between the eyes; the parietal bones are more strongly ridged, 

 the sutures rpore distinct, the top of the cranium beyond the eyes more 



