394 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY - IV. 



HI /',-. /.vi Ajrassi/, Lake Superior, l w .".i'. :in>: Gasierosteua oonrinntu Richardson, Fauna 

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

 (idxIrrotti-iiH i.iuini'iixix Siorer, Boat. Juurn. Nat. Hist, i, 404 (Maine; D. VII-I, 9; A. 

 l.-i. Tli" (\\i last perhaps represent a disUnot subspecies, distinguished l>\ the 



Jil'esenee of? tVce dorsal .spines.) 



Suits. bfucliypoda Bean. 



Similar to puuyitiiis, but the ventral spines very short, their length 

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



Ballhfs Bay to Alaska; abundant. 



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

 bb. Dorsal spines ahout .">, in a right line (Eucalia* Jordan). 



6"27. G. iEBCOlBSlaaas Kirt. Drool: Stickh-bttrl:. 



Males in spring 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, covered by skin. Gill-membranes some- 

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

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

 the flu; anal spine similar to dorsal spines; ventral spines short and 

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

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

 in the Great Lake region. 



(Kirthind, Bo.st. Journ. Nat. Hist. iii. 273, 1841: (latitcmxli'iin micrnjniK Cope, 1'nte. 



Aead. \.-it. Sri. 1'hila. l^tl."), si: Kucidin iin-oimtium .Ionian, 1'ioe. Aead. Nat . Sei. Phila. 

 1-77. C)."i: dnxtiTitxtfux pi/i/niiri/s Agassi/., Lake Snjierior, I-.~U, :5M, from Lake Superior ; 

 this is perhaps a distinct species, dill'ering in the small nnmher of lin-rays : 1). Ill, 1, 

 i'>: A. I, (>. l-'.iu'nlin iiii-nnntiuix var. c(ii/n//a .lordan, Man. \'ert. ;.-"('>, 'J-l'.' : specimens 

 from Cayii.ua Lake, N. Y., with compressed and elevated liody, sh'iiderer tail, and 

 higher .spines : .' dKsti-i-axti K.V u-ill:<iiiimiin\ (iirard, I'. S. ]' ;l c. R. I{. Kxp. and Snrv. x,i>4.) 



aa. Gill-niemliranes not t'n c iVmn the isthmus ; hody more or less mailed. (Haxti /(,- 



t> itn. ) 

 c. Tail naked, nut keeled. J 



.Ionian. Man. Vert. K. I ". S. 1-7C,, J l~ : t \ pe l.,i^t,rnttns iiironxlniin Kirthind. (sv, 

 well ; -. I ... ii'-st.) 



t < li\ aei'nii.-. In-own, darker al-i>\ < ; sides spot ted with Mack : lielly yellowish ; head 

 I', in length; de]ith f> in total length; e\ e i'.l in l.-nuth nf head ; tipoflirst dorsal 



f>pim-not reaching the base of the second. 1>. III-I, n>: A. 1,7. ((;i>-< ni.} Williain- 



hon's I'ass, ( 'alifornia. This form may ditler from (!. inronstnnN in the .smaller nnmlier 

 of dorsal spines. 



-, \eral rei-enl writer> ha\e indicated their lielief that the naked tailed tdickle- 

 hacks an' simple varieties of the ordinary species. This may he true, hut we hi'vo 

 not yet uiet with distinctly intermi'iliate (onus, cither on the Atlantic or 1'acilic coast. 



