DEPARTMENT OF EXPERIMENTAL EVOLUTION. 145 



uals a marked, though much reduced, pigmentation; in others only a 

 trace of pigment is developed; and in still others no pigment can be 

 detected. Enough has been seen to conclude that the difference between 

 the outside normally pigmented form of this species and the cave form 

 without body pigment is more than a mere ontogenetic difference, 

 else the first generation offspring reared in the cave from pigmented 

 parents should develop no body pigment. 



As throwing light on the albinism of cave forms, Dr. Banta has made 

 some observations on albinos in general. He has published a note 

 giving a number of chance observations on albinos occurring in nature. 

 One of these is the case of a persistent albino strain of the gray squirrel 

 in nature and another is of an albino strain of Asellus, which, noted in 

 the same locaUty for three years, has come to form a notable proportion 

 of the population. It seems here to have undergone no differential 

 elimination. 



Exploration of caves. — A collecting trip made by Dr. Banta to the 

 cave region in the Stockbridge limestone (marble and limestone) region 

 of eastern New York, western Connecticut, western Massachusetts, 

 and Vermont proved to be unexpectedly productive. This region 

 contains numerous small caves, each in general known only to people 

 living in its immediate vicinity. These caves are difficult to find and 

 most difficult ones in which to collect. The high altitude of most of 

 these caves is conducive to a hmited water content and the sharp tilt 

 of the limestone or marble strata brings about a rapid and complete 

 drainage which is unfavorable for the occurrence of pools suitable foi 

 aquatic life. Suitable pools were found in only tliree of the eleven 

 caves visited in this region. Of these, Newton's Cave, near Pittsfield, 

 yielded no aquatic fauna, although conditions seemed favorable for 

 such life, but in the Twin Lakes Caves near Canaan, Connecticut, 

 two interesting typical cave animals were found, a pigmentless plana- 

 rian and a small, eyeless and pigmentless amphipod. One of these 

 species may prove identical with a similar form from the cave region 

 in central New York, but this is doubtful. The occurrence of these 

 highly modified species in New England caves from which no real cave 

 fauna had been obtained previously is of much interest. In addition 

 were secured a myriapod, a mite, and a thysanuran, all apparently 

 more or less typical cave animals. 



OTHER INVESTIGATIONS. 



CORRELATION BETWEEN FERTILITY OF A PLANT AND ITS SOMATIC CHARACTERS. 



The abihty of a species or strain to hold its own in nature depends, 

 among other things, on its fertility in relation to that of other, closely 

 related, species. Dr. Harris has pubhshed a painstaking investigation 

 into the relation between fertility in garden beans — or the average 

 number of mature seeds that a plant produces per pod — and the 



