26 THE BLIND FISHES OF .MAMMOTH CAVE. 
Anal opening. In normal posi- Forward ofpec- The same. The same. 
tion. torals.t 
Air bladder. Present in few Present. The same. The same. 
genera.} 
Scales. On body regu- Irregularly ar- The same. The same. 
larly imbricat- ranged, firm- 
ed ow luosely ly attached 
attached. by being cov- 
ered in great 
part by the 
cuticle. 
Head with scales With scales. Naked. The same. The same. 
naked.§ 
Tactile papille || Absent. Absent. Very prominent The same. 
on the heud and as ridges on 
body. the head and 
sid f body 
Ventral fins.T Present in most Absent. Absent. Present. 
enera, absent 
n at least two. 
Eyes.** wee developedin Well eee ag Rudimentary tt The same. 
an rma and of no use 
Habitat. ed er; Limestone wa- Limestone wa- Thesame. | 
brackish water} ter of subter- ter oS abt 
salt w ranean riv- ranea 
os EE NR 
wat 
Geographical + Nearly all parts of One eA in Gentral & south- oane and 
range. the world. i cela a y ern portion of . central 
streams of S. subterranean N idon of 
central por- fauna of Unit- same. 
tion in Mone the U. ed States. 
cies io the 
an coas biai 
of U. S. 
From this brief comparison ‘6 some of the prominent charac- 
ters of the genera of the Heteropygii with the Cyprinodontes, their 
pi eek: E cee 
Ina + A ath eo At m 4 + thie forward 
position of the anus beg 0. 
t The air bladder is in several families present in some species and in others 
iS ae presence oF - absence of scales on the head, or inten portions of it, ool = Ngee! 
{| I cannot recall anything but the barbels on the head ‘and jaws of many Apii n of 
Cyprinoids, Siluroids, Gadoids, ete., etc., that can be said to be tactile organs, among 
; fishes, f papillæ on the head and body of the blind fishes 
K of the a and Cuban caves, and the filaments of the fin rays of map $ 
and the flesh rays o. Gurnards. ; 
ST Of all iii the ventrals are the most nape to deviate from their normal stru 
and position. Their presence or seen in exhibited in man families and onen noy 
different ages ot the same fish, a the great variation in their position in differe 
of the same family, v are hange in them of either pate , specific, OF 
individual character, 0 bees indicative of age (as they are lost in so me adult pei E 
— s piar in th you e other bot 
i rt f this paper, thori eyes 
the constant and srarins part of the fish structure than t the Kontrat ias, pand i 
re f. th 
Pie 
like them are eubject t 
. perfection in structure. 
5 Sat "E pe e ae sn Jon 
and as the eye of an Amblyopsis « of twice the sizo is not over a 32d of an inch oo width, , 
it must be very small indeed in Ty to find it 
in an ordinary dissection, assisted only by a god lons. 
