MUSEUM OF COMPARATIVE ZOOLOGY. 87 
developed on the head and sides of the body of both Amblyopsis and 
Typhlichthys. According to Packard (’86, p. 127), Tellkampf regarded 
these papille ‘as without doubt increasing the tactile sense.” I have 
not seen this paper of Tellkampf’s, and do not know whether his mean- 
ing would be that the tactile sense is increased as compared with what 
it was in the same species before it was deprived of sight, or merely 
that it is great as compared with other bony fishes. Leydig also be- 
lieves that the tactile organs perform such a compensatory office (’83; 
see also Wright, ’84, p. 272). Packard (’86, pp. 127, 128) gives ex- 
tracts from several letters of Dr. John Sloan that are interesting in 
this connection. Although the writer does not expressly state his belief 
that the sense of touch has been highly developed for the purpose of 
compensating the lack of sight, he still gives very convincing evidence 
of its extreme acuteness from personal observation on the fishes in their 
native surroundings. It should also be noticed that he specially tested 
their powers of hearing and the effect of light upon them, and to both 
he says they “ manifested total indifference.” Sloan’s observations were 
on Amblyopsis. Wyman (’72, p. 19) has described the ear of this spe- 
cies as being “largely developed” in all its parts, and Cope (’72, p. 410) 
found the sense of hearing “evidently very acute.” As to the ques- 
tion whether the sense papillz in Amblyopsis and Typhlichthys are in 
reality developed as a compensation for the loss of sight, the testimony 
furnished by Chologaster is of the greatest importance. Although this 
genus was discovered and named by L. Agassiz in 1843, its characters 
were best made known by Putnam. He (’72, pp. 22, 23) says: “In the 
genus Chologaster we have all the family characters as well expressed 
as in the blind species, though it differs from Amblyopsis and Typhlich- 
thys by the presence of eyes, and the absence of papillary ridges on 
the head and body, and by the longer intestine and double the number 
of pyloric appendages, as well as by the position of the ovary.” 
In 1881, 8. A. Forbes (’82, p. 3) discovered a fish in Southern Illinois 
which he identified as belonging to the genus Chologaster, but repre- 
senting a new species. With reference to the point that we are now 
considering, the author writes: “The most important and interesting 
peculiarity of this species indicates a more advanced stage of adap- 
tation to a subterranean life than that of its congeners. On all the 
surfaces of the head appear short rows of peculiar tubercles. . . . 
When thus exposed [by being freed from the adjacent epidermis], they 
closely resemble the papillae of Amblyopsis in form and size, and are 
similarly cupped at the tip.’ Again (p. 5) he says: ‘‘The extraor- 
