Jordan and Evermann. Fishes of North America. 1063 



series of small, squarish olive or bluish blotches along the back and 

 another along each side ; lateral spots connected by a gilt band. Length 

 3 inches. Lake Erie to Minnesota, Kentucky and Texas ; abounding in 

 clear sandy streams; one of the most interesting of our fishes, burying 

 itself in the sand by an instantaneous* movement, leaving only its eyes 

 and snout visible, (pellucidus, transparent.) 



Pleurolepis pellucidus (BAIRD MS.) AGASSIZ, Bull. Mus. Comp. Zool., I, 5, 1863, no locality; the 

 specimens from Black River, Ohio, the types of Etheostoma pellucidum, BAIRD MS., 1853, 

 (Type, No. 1311. Coll. Baird); VAILLANT, Recherches, 138, 1873, with plate. 



Pleurolepis pellucidus, JORDAN & COPELAND, Amer. Nat., 86, 1877. 



Amniocrypta pellucida, JORDAN & GILBERT, Synopsis, 489, 1883; BOULENGER, Cat., i, 102. 



Represented northwestward by 



1450a. AMMOCRYPTA PELLUCIDA CLARA (Jordan & Meek). 



This variety differs from the typical pellucida in having no scales along 

 the nuchal region, and none on sides anteriorly, except the 5 or 6 rows 

 along the lateral line ; cheeks with few scales. It grades into the typi- 

 cal pellucida, although extreme forms are readily recognizable ; scarcely 

 worthy of separation from the species. Mississippi Valley, Wabash 

 River, west to central Iowa and Minnesota and south to Arkansas and 

 northern Texas, (clarus, clear.) 



Ammovrypta clara, JORDAN & MEEK, Proc. U. S. Nat. Mus., 1885, 8, Des Moines River, 



Ottumwa, Iowa. (Type, No. 35828. Coll. Jordan & Meek.) 

 Etheostoma pellucidum clarum, EVERMANN & JENKINS, Proc. U. S. Nat. Mus., 1888, 49. 



Represented southwestward by 



U50b. AMMOCRYPTA PELLUCIDA VIVAX (Hay). 



More fully scaled than typical pellucida, the region before the dorsal 

 being more or less closely covered with scales; scales firmer and rougher. 

 A dusky bar across base of soft dorsal. In other respects essentially as 

 in pellucida. Pyloric coaca 4. Vertebra 21 -f- 20 = 41. Length If inches. 



a swift beating of the tail to right and left was in less than five seconds completely buried. The 

 sand had been violently stirred of course, and just as it had nearly settled, probably in less than 

 half a minute, its nose was put quietly out, and settling back left the twinkling eyes and narrow 

 forehead alone visible. Since then we have kept scores of them in an aquarium arranged 

 especially for their convenience and have often seen them burrow into the sand. They will remain 

 buried so long as the water is pure and cool. Indeed, we now rely almost entirely on them to 

 warn us when the water needs changing. When this need is felt they come out of the sand and 

 lie on the bottom panting violently. We have been unable to discover any immediate incentive 

 for the act. It seems to be entirely unpremeditated. A number of them in confinement lio 

 helplessly on the bottom, motionless and slowly breathing, when one suddenly starts and buries 

 his head and neck in the now whirling sand; by a motion as quick as thought, his tail beats 

 frantically about and when again the clean sand lies smooth on the bottom the little eyes are 

 looking at you like two glistening beads, as if to witness your applause at so clever a trick. 

 We have never seen Ammocrijpta taste of food, nor do we ever expect to do so; for although its 

 mouth bristles with teeth, its small size forbids an attack on any game which we can offer. Its 

 quiescent habits and the character of the bottoms to which it confines itself seem to indicate that 

 its prey is minute if not microscopic. But speculation about what we do not know as to its food 

 might lead us to speculation as to the origin of its characteristic features how, for instance, the 

 hard snout, the transparent muscles, and the burrowing habits are consequent on its loss of scales, 

 or how the loss of unnecessary scales and of pigment cells is consequent on its burrowing habits. 

 Then, when we have finished these matters, we might inquire how it came about that there are 

 " Johnny Darters " at all, and why no other continent has them. Jordan & Copland. 



