394 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 



mhnloam Af^assiz, Lake Superior, 1850, 310: Gastcrostcus concinnus Ricliardson, Fauua 

 Bor.-Amer. Fishes, 57 (Saskatchewan River and Great Bear Lake ; D. VII-I, 9 ; A. 1, 8) : 

 GasI.ero'itcus iiiainciisis Storer, Bost. Journ. Nat. Hist, i, 464 (Maine; D. VII-I, 9; A. 

 I, 8). Tho two last pei'haps represent a dlsLinut subspecies, distinguished by the 

 presence of 7 free dorsal spines.) 



Subs, braclaypoda Beau. 



Similar to pungitius, but tlie ventral spines very short, tlieir lengtli 

 a little less than one-third that of the head. D. X-I, 10; A. I, 10. 

 Baffin's Bay to Alaska; abundant. 



(Bean, Bull. U. S. Nat. Mus. xv, 129, 1879.) 



bb. Dorsal spines about 5, in a right line {Eucalia'^ Jordan). 

 627. G. iEacOHStanns Kirt. — Brook Sticlckbacl: 



Males in spriug: jet black, tinged with red anteriorly; females and 

 young olivaceous, mottled, and dotted with black. Body moderately 

 elongate, little compressed, the caudal peduncle comparatively stout, 

 not keeled. Skin smooth, entirely destitute of dermal plates, the skele- 

 tal plates covered by it. Innominate bone small, lanceolate, covered by 

 the skin. Space in front of pectorals small ; thoracic processes very 

 slender and widely separated, (;overed by skin. Gill-membranes some- 

 what free posteriorly; gill-rakers short. Dorsal spines four or five, low, 

 subequal, in a right line, a cartilaginous ridge running along the base of 

 the fin; anal si^ine similar to dorsal spines; ventral spines short and 

 sharp, serrated. Head 3^; depth 4. D.IV-1, 10; A. 1, 10. L. 2 J inches. 

 New York to Kansas and Greenland, in fresh waters only; abundant 

 in the Great Lake region. 



(Kirtland, Bost. Journ. Nat. Hist. iii. 273, 1841: Gasterosteus mlcropus Cope, Proc. 

 Acad. Nat. Sci. Phila. 1805, 81: EHCuliainconstans JonXan., Proc. Acad. Nat. Sci.Phila. 

 1877, 65: Gatita-ontt^is pygiiuEus Agassiz, Lake Superior, 1850, 314, froui Lake Superior ; 

 this is perhaps a distinct species, differing in the small number of lin-rays ; D. Ill, I, 

 6; A. 1,6. Eucalia inconstans var. cayufja Jordan, Man. Vert. 1876, 249; specimens 

 from Cayuga Lake, N. Y., with compressed and elevated body, slenderer tail, and 

 higher spines : ? Gasterosteus zcillhinisonii Girard, U. S. Pac. R. R. Exp. and Surv. x, 94.) 



aa. Gill-membranes not free from the isthmus ; body more or less mailed. {Gasteros- 

 teus. ) 

 c. Tail naked, not keeled, t 



* Jordan. Man. Vert. E. U. S. Ib76, 248: tyjie Gasterosteus inconstans Kirtland. (cv, 

 well ; xaAia, nest.) 



t Olivaceous brown, darker above; sides spotted with black; belly yellowish; head 

 3 in length; depth 5 in total length; eye 3^ in length of head; tip of first dorsal 

 spine not reaching the base of the second. D. 111-1,10; A. 1,7. (G'inrrf. ) William- 

 sou's Pass, California. This form may differ from G. inconstans in the smaller number 

 of dorsal spines. 



t Several recent writers have indicated their belief that the naked tailed stickle- 

 backs are simple varieties of the ordinary Sftecies. This nuiy be true, but we ht've 

 not yet met with distinctly intermediate forms, either on the Atlantic or Pacific coast. 



