MICROPERCA 317 



Genus MICROPERCA Putnam 



Body short and stout; mouth small, slightly oblique; premaxillaries not 

 protractile; vertebrae (M. -punctulata) 30 (16 + 20); differing ivom Etheostoma 

 only in the almost or complete absence of the lateral line; the vertebrae and 

 fin rays fewer than in other darters, and the scales larger than in most species. 

 Size extremely small — the smallest of the darters; coloration plain; species 

 few, or perhaps not more than one. 



MICROPERCA PUNCTULATA Putnam 



LEAST DARTER 

 (Map XCIX) 



Putnam, 1863, Bull. Mus. Comp. Zool., I, 4. 



J. & G., 523; M. V., 134 (Etheostomla microperca) ; B., I, 87 (Etheostoma micro- 

 perca); J. & E., I, 1104; N., 34; J., 43; F., 64; F. F., I. 3, 24; L., 29. 



Length 1 to IJ^ inches; body not much elongate^ compressed, the back 

 moderately arched; depth 4.6 to 5.2; greatest \\'idth about Yj of greatest 

 depth; depth caudal peduncle 2.6 to 3.1. "Coloration olivaceous, the sides 

 closely speckled and with vague bars and zigzag markings; second dorsal and 

 caudal barred; dark streaks radiating from eye; a dark humeral spot" (Jordan 

 and Evermann). Head bluntly rounded, 3.6 to 4; width of head 1.9 to 2.2 

 in its length; interorbital space 6.7; eye 3.7 to 4.1; nose 4.8 to 5.5; mouth 

 terminal, obHque, maxillary to middle of orbit, cleft 3.5 to 4 in head; jaws 

 equal; gill-membranes scarcely connected. Dorsal VI, 9; spinous and soft 

 dorsals separated by a space about equal to pupil; anal II, 5 or 6; separation 

 of ventral less than half width of base; pectorals equahng head. Scales large 

 and strongly ctenoid; 33-36, oblique series 9 or 10; lateral Hne absent; cheeks 

 naked; opercles with a few scales; breast and neck naked. 



This, the smallest of the darters and the smallest, indeed, of 

 our spiny-finned fishes, is very rare in om- collections outside 

 those from the upland lakes of northeastern Illinois. We have 

 taken it, in fact, but twice south of Joliet, in Will county, the 

 exceptional instances coming from Skillet fork in Wayne county, 

 and from Drury creek in Union county, in the southern part of 

 the state. It has been wanting, it will be seen, in all our central 

 Illinois collections. 



