FUNDULUS K1LLIFISHES 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, " feeding on surface-swimming insects, etc. 



FUNDULUS DIAPHANUS MENONA (JORDAN & COPELAND) 



MENONA TOP-MINNOW 



(MAP LXIII) 



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

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



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

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



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

 peduncle long; depth 4.5 to 5.3; greatest width about % of greatest depth; 

 depth caudal peduncle 2.2 to 2.4 in its length. Color (males) light olivaceous, 

 spotted with dusky 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 silvery 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, maxillary 3.6 to 4 in head, 

 mandible equal to eye, lower jaw slightly 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; pectorals 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 Pceciliidce, preceding. 



