FUNDULUS KILLIFISHES 211 



Genus FUNDULUS Lacepede 



(killifishes) 



Body rather elongate, little elevated, compressed behind; head broad 

 and flat above; mouth moderate, lower jaw projecting; jaws each with 2, 

 or more, series of pointed teeth; preopercle, preorbital, and mandible 

 with conspicuous mucus pores; dorsal and anal fins rather similar in 

 size, either large or small, the anal slightly higher in males of some species 

 than in females, but not developed as an intromittent organ; scales 

 moderate. 



Species very numerous, mostly American, inhabiting the fresh 

 waters of the interior and the arms of the sea, on both coasts. All 

 are oviparous. They are all carnivorous in greater or less degree. 

 The three species found in Illinois* are typical "top-minnows," feed- 

 ing on surface-swimming insects, etc. 



FUNDULUS DIAPHANUS MENONA (Jordan & Copeland) 



(menona top-minnow) 



Le Sueur, 1817. J. Ac. Xat. Sci. Phila., 130 (Hydrargira diaphana). 

 Jordan & Copeland, 1877, P. Ac. Nat. Sci. Phila., 68 (menona). 



I. &G., 335 (menona): M. V., 85; J. & E., I, 645; X., 42 (diaphanus^ ; J.. 52 (menona); 

 F., 72 (diaphanus); F. F., I. 6, 71 (diaphanus) ; L., 21. 



Length 3 inches; body rather slender and not much compressed, cau- 

 dal peduncle long; depth 4.5 to 5.3; greatest width about f of greatest 

 depth; depth caudal peduncle 2.2 to 2.4 in its length. Color (males) 

 light olivaceous, spotted with duskv on back and on sides above lateral 

 line; 15 to 20 dark transverse bars on each side, reaching from back 

 to belly, broader than the silvery interspaces; belly silvery white; opercles 

 emerald, dusted with dark specks; an emerald-green spot behind opercle; 

 iris mingled iridescent emerald to lavender, with a narrow inner rim of 

 gold next to pupil; fins pale, dorsal with a faint longitudinal bar of dusky 

 near base ; base of caudal with a squarish golden spot. Females have dark 

 bars shorter and narrower than in males, and the interspaces wider than 

 the bars, olivaceous, without silver\' luster; dorsal fin without dark bar. 

 Head quite flat above, 3.5 to 3.9; width of head 1 .9 to 2 .2 in its 

 length ; interorbital space 2 . 8 to 3 . 1 in head ; eye 3 to 3 . 5 ; nose 2 . 9 to 

 3.7, usually more than 3.3; mouth small, maxillarv 3 . 6 to 4 in head, 

 mandible equal to eye, lower jaw slightlv projecting; teeth pointed, 

 curved, the outer ones scarcely enlarged. Dorsal inserted in front of 

 ventrals, its rays 13 or 14; anal rays 11; ventrals short of vent; pecto- 

 rals 1 . 7 to 1 .9 in head. Scales 43 to 45; transverse series 14 or 15; no 

 lateral line; cheeks and opercles covered with large scales. 



*For key to species, see key to genera and species of Pcsciliidce, preceding. 



