192 Cocherell (ind Callmvay — Fishes of the Genus N^utropis. 



The scales of this subgenus are thin, and often very feebly scul[)ture(l. 

 iV. mtiskoka from Orillo, Ontario, has quite strongly sculptured scales, 

 with the uiaxiniuin nnnil)er of radii for this group, sometimes as many as 

 24, counting the rudimentary ones. It should therefore Tie regarded as 

 the nearest to the stem-form of Cliriope.* 



The following table is based on the scales : 

 Scales broader than long. 



Scale much broader tlian long. 



Sculpture distinct, radii IS to 24 X miiskuka Meek. 



Sculpture weak. 



Radii 11 to i:! iV''. /.r;ufa?/j Evermann & Cockerell. 



Uadii or 10 X. cnyiiga ]Meek. 



Scale somewhat broader tlian long. 



Sculpture distinct; size medium; radii 14 to 20 . N. heterodon Cope. 



Indiana. 

 Sculpture distinct; size small; radii 9 to 11 . . N. bifrenatus Cope. 

 (N. heterodon has tliin scales, the radii irregular and wavy. ) 

 Scales subcircular. 

 Scale large; sculpture distinct ; radii 12 or 13 . X.atrocandalisEyerm. 



Palestine, Te.xas. 

 Scale small; sculpture weak. 



Radii 12 or 1. "J X. anogenus Forbes. 



Radii 7 or S . . .V. maculalus (Hay). 



X. bifrenatus agrees witli heterodon in having the scales broadly rounded 

 apically. 



A provisional scheme of evolution may l)e suggested — 



atTOcaudalis macidatus (Southern) heterodon (Western) 



(Southwestern) / cayvga (Western) Icendalli (Eastern) \ bifrtnatus (Easteru) 



muakoia (Northern) 



Figure 1. 



X. jordani Eigenm. &. Eigenm. has not been seen. 



Chriope appears to have developed from a huxiloid type independently 

 of the other suligenera; or at least, the other subgenera are not in its an- 

 cestry. 



Ai.r.ruxoi's ( Jirard. 



We know little al)out this grou]i, having nnly thn-e species. So far as 

 the scales go, the obvious suggestion would be that X. hlennius arose from 

 tlie muskoka type. It is a small Hsh with large, thin, exceedingly broad 

 scales, greatly resembling those of muxkoka. It has more radii than the 

 other two species examined. X. spectrunculus has the scales much smaller, 

 with more distinct sculpture. iV. sci/lla is in .some ways intermediate. 



• .VccoiiliiiK Id Uic ttH'th, y. lieUi-ixlon, witli iri.tli sometimes 2, 4-4, 2, as in Luxihis, 

 should mtlior be llie stem-ionn. 



