247 
Fig. 7. Utriculus and canalis externus. Cross section showing the 
macula neglecta. x 195. 
Fig. 8. Lagena. Cross section showing the capilla acustica. x 195. 
Fig. 9. -Ampulla anterior. Longitudinal section. Cross section of 
erista. x 195. 
Fig. 10. Utriculus. Cross section showing the macula neglecta. 
x % obj. 2 in oc). 
Fig. 11. The three otoliths drawn to the same magnification. The 
largest belongs to the sacculus; the smallest to the lagena, and the other 
to the recessus utriculi. x 23. 
A CASE OF CONVERGENCE.* By Cart H. EIGENMANN. 
In 1859 Girard (Proc. Acad. Nat. Se., Phila., p. 62) described a small 
blind fish, Typhlichthys subterraneus from Bowling Green, Ky. This 
species has since been found to be abundant in the subterranean waters 
east of the Mississippi and south of the Ohio. 
In 1889 Garman (Bull. Mus. Comp. Zool. XVII, No. 6) gave an account 
of a blind fish from some caves in Missouri. Mr. Garman says: ‘‘Com- 
pared with specimens from Kentucky and Tennessee, they agree so ex- 
actly as to raise the question whether the species was not originated in 
one of the localities and thence distributed to the others. * * * There 
is no doubt that the representatives of Typhlichthys subterraneus in the 
various caves were derived from a single common ancestral species. The 
doubts concern only the probability of the existence of three or more lines 
* Contributions from the Zoélogical Department of the Indiana University, No. 27. 
