miller's thumb. 989 



«ent " nnder stones in clear gravelly brooks, after the manner of the Darters. This 

 species has not yet been noticed in Ohio, but it may probably be found in tributaries 

 of Lake Erie, in the north-eastern part of the State. 



161. Uranidea KICHABD30NI (Agassiz) Jordan and Gilbert. 

 miller's Thnnib; Blob; muffle-Jaws; Cave Bull-head. 



a. var. ticKardioni. (Upper Lakes.) 



Cottuerichardgoni, Agassiz, Lake Superior, 1850, 300 ; Gikard, Mon. Cotb,, 1850, 39.— GUN- 

 THKK, ii, 1850, 158. 



6. var; iairdi. (Ohio to N. Y.) 

 Cottus iairdi, Girakd, Proc. Am. Ass. Adv. Sol., 1850, 410 ; and Mon. Cott , 44. 



c. var. wilaoni, (Ohio Valley.) 

 Coitus wilsoni, Girard, Mon. Cott., 1851, 42. 



d. var. alvordi. (Wisconsin and Michigan.) 

 Cottus alvordi, Girard, Mon. Cott., 1851, 46. 



e. var. meridionaUs. (Alleghanies. ) 

 Cotlua meridionalis, Girasd, Proc. Ass. Adv. Sci., 1850, 410 ; and Mod. Cott., 1851, 47. 



/. var. zopherus. (Alabama basin.) 

 Potamoeottvs zopherus, Jordan, Ann. Lyo. Nat. Hist. N. Y., 1876. 



g. var. carolinw. (Ohio Valley and southward.) 



Potamocottus caroUnw, Gill, Proc. Bost. Soc. Nat. Hist., 1861, 40. 



Description. — Olivaceous, more or less barred and speckled with darker ; fins mostly 

 barred or mottled ; body slender or stout, tapering regularly backward to the tail ; ver- 

 tex somewhat depressed ; interoonlar space with a groove ; preopercle with a short, 

 eharp spine, little hooked, directed backwards and upwards, mostly covered by the 

 skin ; below this are 2 smaller concealed spines ; subopercle with a stoutish spine, 

 directed forwards; sMn smooth, except the region immediately behind the pectorals, 

 which is beset with very small sharp prickles ; these are sometimes obsolete ; lateral 

 line conspicuous, continuous or interrupted behind ; first dorsal low and feeble ; pectoral 

 fins large, their length nearly equal to that of the head, their tips usually reaching be- 

 yond the origin of the soft dorsal ; ventral fins moderate ; isthmus very broad, the gill- 

 membranes not forming a fold across it ; head aj ; depth 4-6 ; D. VI to VIII, 16 or 17 ; 

 A. about 12 ; V. I, 4. Length 3 to 6 inches 



Habitat, Middle and Northern States, and probably northward ; abounding in all clear 

 rocky brooks and lakes southward along the Alleghanies. 



Note. — As understood by us, Uranidea richardsoni is a wide spread and abundant species, 

 varying in different regions, as is th» case with most non-migratory species. In this as 



