70 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. [1885. 



8. Diplesion blemyoides, Rafinesqxie. 



Frontal region very narrow. Ethmoid region abruptly decurved. Pa- 

 rietal region rather convex ti-ansversely, rather broad, the bones finely 

 striate, with obscure sutures. No supraoccipital crest. Suprascapula 

 very short. Scapula rather broad, L-shaped. Profile low posteriorly, 

 full above eyes. Skull more flattened above than in JEtheostoma, but 

 less so than in Cottogaster, Eadropterus, &c. Pyloric coeca 4. Verte- 

 brae 19 + 23 = 42. 



This species approaches more closely to Etheostoma than do any of 

 the preceding, so far as the form of the cranium is concerned. The 

 group of which Etheostoma zonale is the type apparently marks the tran- 

 sition from the one series to the other. 



9. Boleosoma maculatum, Agassiz. 



Frontal region short, very narrow. Parietal region tiattish above, its 

 bones faintly striate. No supraoccipital crest. Profile most convex 

 above front of eye. Suprascapular processes slender. Pyloric coeca 6. 

 Vertebrae 15 + 22 = 37. 



10. Boleosoma camurum, Forbes. 



Skull essentially as in B. mnculatum. Pyloric coeca 3. Vertebrse 

 17 + 21 = 38. 



11. Ammocrypta pellucida, Bainl. 



Frontal region narrow. Parietal region depressed, flattish ; the bones 

 thin, nearly smooth. Sutures very distinct. Supraoccipital crest ob- 

 solete. Profile highest above posterior i)art of eye. Ulnar foramen very 

 large. Scaiiula and suprascapula sleuder; all the bones of the body 

 comparatively slender and thin. To]) of head rather more flattened 

 than in any other geuus. Pyloric (;feca 4. Vertebriie 23 + 21 = 44. 



12. Ammocrypta vivax, Hay. 



Skeleton essentially as in A. pellucida,, tte sutures of the skull per- 

 haps less distinct. Vertebrae 21 + 20 = 41. Pyloric cu^ca 4. 



The remaining species, now referred to Etheo.stoma and Microperca, 

 agree very closely with one another in the form of the cranium, which 

 is narrow behind the eyes, across the jiarietal region, and very strongly 

 convex transversely. In these species the vertebrse are more or less re- 

 duced in number and there are usually fewer rays in the spinous dorsnl 

 and anal. 



13. Etheostoma zonale, Cope. 



Frontal region very short, moderately narl'ow. Parietal region very 

 strongly convex transversely, the bones with radiating strise. No su- 

 praoccipital crest. Profile most prominent above po.sterior part of eye. 

 Pyloric coeca 4. Vertebra? 16 + 23 = 39. 



This species differs from the others referred to Etheostoma chiefly in 

 the shortness and decurvature of tha frontal region". 



