ne of them, the Quedius speleus, Horn, is half an inchin 
ngth, and has rather small eyes; it was found not far 
from the mouth of the cave. Dr. Horn furnishes me with 
the following list of Coleoptera from the two caves in 
question :— 
Anophthalmus Tellkampfii Erichs. Mammoth Cave. 
. a enetriesi Motsch, angu- 
‘ latus Lec. Mammoth Cave. 
4 eremita Horn. Wyandotte Cave. 
tenuis Horn, 
Wyandotte Cave. 
striatus Motsch. 
Mammoth Cave, Unknown to me. 
< = ventricosus Motsch, Mammoth Cave. Unknown to me. 
delops hirta Tellk. Mammoth Cave. 
_ These are the only true cave insects at present known 
in these faunze. Other species were collected within the 
mouths of the caves, but which cannot be classed with 
the preceding, as cave insects proper. 
5 ” 
Be Catops n. sp.? Wyandotte Cave. 
." teen spelzeus Horn, Wyandotte Cave. 
estev n. spa, Wyandotte Cave. 
And another Alzeocharyde Staphylinide, allied to Zachy- 
usa, also from Wyandotte Cave. No names have as yet 
been given to any of these, excepting the second. A 
ionograph of Catops has already appeared containing 
‘many species from our fauna ; and as the work is inacces- 
sible at present, I have hesitated to do more than indicate 
the presence of the above species. 
_ The cricket of the Wyandotte Cave is stouter than that 
_ of the Mammoth, and thus more like the Raphidophora 
_lapidicola of the forest. There were three species of flies, 
one or more species of Poduride, and a Campodea not 
determined. : 
Centipedes are much more abundant in the Wyandotte 
than in the Mammoth Cave. They especially abounded 
on the high stalagmites which crown the hill beneath the 
Mammoth dome, which is three miles from the mouth of 
the cave. The species is quite distinct from that of the 
Mammoth Cave, and is the one I described some years 
ago from caves in Virginia and Tennessee. I call it 
Spirostrephon cavernarum, agreeing with Dr. Packard 
that the genus Pseudotremia, to which it was originally 
referred, is of doubtful validity. The allied form found by 
‘Mr. Cooke in the Mammoth Cave has been described by 
Dr. Packard as Sfirostrephon Copet. It is eyeless, and 
is, on this account alone, worthy of being distinguished 
_ generically from Spzrostrephon. This genus may be then 
named Scoterpes. 
narum in the Mammoth Cave. 
_ Two species of Arachnidans were observed, one a true 
spider, the other related to the “long-legs” of the woods. 
_ A species similar to the former is found in the Mammoth 
Cave, and others in other caves, but in every instance 
_ where I have obtained them they have been lost by the 
_ dissolution of their delicate tissues in the impure alcohol. 
_ The other forms are more completely chitinised, and are 
easily preserved ; they are related to the genus Gony/eptes, 
found under stones in various portions of the country. 
_ Dr. Wood describes a species from Texas, and I have 
_taken them in Tennessee and Kansas. In the Wyandotte 
‘Cave I found a number of individuals of a new species, at 
_ aplace called the screw-hole. Though living at a dis- 
‘tance of four or five miles from the mouth of the cave, 
this species is furnished with eyes. This species is 
described as Evebomaster flavescens Cope. In its rela- 
tionships it may be said to stand between Acanthocheir 
_ and Gonylepies. 
Besides Acanthocheiy, another blind Gonyleptid exists 
in the Mammoth Cave, which I found several miles from 
‘the mouth. It is blind like the former, but differs in 
_ having many more joints to the tarsi, approaching thus 
the true Pialangia, or long-legs. 
__ Dr. Packard and Mr, Putnam have already discussed 
_ the question of the probability of the origin of these blind 
cave animals by descent from out-door species having 
eyes. I have already expressed myself in favour of such 
_ view, and deem that in order to prove it we need only 
¥ 
I look for the discovery of S. caver-~ 
establish two or three propositions. First, that there are 
eyed genera corresponding closely in other general cha- 
racters with the blind ones ; second, that the condition of 
the visual organs is in some cave type variable ; third, if 
the abortion of the visual organs can be shown to take 
place coincidently with general growth to maturity, an 
important point is gained in explanation of the modus 
operandi of the process. 
First, as to corresponding forms; the 7yphlichthys of 
the Mammoth is identical with Cho/ogaster, except in its 
lack of eyes. Ovconectes bears the same relation to Cam- 
barus ; Stygobromus bears nearly the same to Gammarus ; 
and Scoterpes is Spirostrephon without eyes and no pores. 
Secondly, as to variability. I have already shown that 
in Gronias nigrilagris, the blind Silurid from the Cones- 
. toga in Pennsylvania, while all of several specimens 
observed were blind, the degree of atrophy of the visual 
organs varies materially, not only in different fishes, but 
on different sides of the same fish. In some the corium 
is imperforate, in others perforate on one side, in others 
on both sides, a rudimental cornea being thus present. 
In some the ball of the eye is oval, and in others col- 
lapsed. This fish is related specifically to the Asmzurus 
nebulosus of the same waters, more nearly than the latter 
is to certain other Amiuri of the Susquehanna river basin 
to which the Conestoga belongs, as for instance the 
A, lynx; it may be supposed to have been enclosed in a 
subterranean lake for a shorter time than the blind fishes 
of the Western Caves, not only on account of the less 
degree of loss of visual organs, but also in view of its very 
dark colours. 
Thirdly, it is asserted that the young Orconectes possess 
eyes, and that perhaps those of the 7yphdichthys do also. 
If these statements be accurate, we have here an example 
of what is known to occur elsewhere, for instance, in the 
whalebone whales. In a feetal stage these animals pos- 
sess rudimentary teeth like other Cetacea, which are sub- 
sequently absorbed. This disappearance of the eyes is 
regarded with reason by Prof. Wyman as evidence of the 
descent of the blind forms from those with visual organs. 
I would suggest that the process of reduction illustrates 
the law of “retardation,” accompanied by another phe- 
nomenon. Where characters which appear latest in em- 
bryonic history are lost, we have simple retardation— 
that is, the animal in successive generations fails to grow 
up to the highest point, falling farther and farther back, 
thus presenting an increasingly slower growth in this 
special respect. Where, asin the presence of eyes, we 
have a character early assumed in embryonic life, the re- 
tardation presents a somewhat different phase. Each 
successive generation, it is true, fails to come up to the 
completeness of its predecessor at maturity, and thus ex- 
hibits “retardation ;” but this process of reduction of rate 
of growth is followed by its termination in the part long 
before growth has ceased in other organs. This is an 
exaggeration of retardation. Thus the eyes in the Or- 
conectes probably once exhibited at maturity the incom- 
plete characters now found in the young, for a long time 
a retarded growth continuing to adult age before its ter- 
mination was gradually withdrawn to earlier stages. 
Growth ceasing entirely, the phase of atrophy succeeded, 
the organ became stationary at an early period of general 
growth, being removed, and its contents transferred to 
the use of other parts by the activity of “ growth force.’ 
Thus, for the loss of lateassumed organs we have < retard- 
ation,” but for that of early assumed ones, “retardation 
and atrophy.” I ; 
The mutual relations of this cave life form an interest- 
ing subject. In the first place, two of the beetles, the 
crickets, the centipede, the small crustaceans (food of the 
blind fish) are more or less herbivorous. They furnish 
food for the spiders, crawfish, Anophthalmus, and the 
fish. The vegetable food supporting them is in the first 
place fungi which, in various small forms, grow in damp 
