232 PROCEEDINGS OF THE NATIONAL MUSEUM. 



O. peUacldus is perf ectl}^ normal, but it can not 1)0 claimed that it is a 

 functional organ of hearing-. The powers of equilibration in C. fellu- 

 cidus are in no way inferior to those of the terranean species with 

 well-developed eyes. It seems to me that the removal of the otocysts 

 in such a blind species and the careful study of the animal's powers 

 thereafter would give a basis for very definite conclusions as to their 

 functions. 



In a series of twent}' specimens collected in the Roaring River 

 passage ten were females, five were males of Form I, and five were 

 males of Form 11. One of the males of Form I is quite soft, and I 

 therefo]-e infer that ecydysis occurs in this species at about the same 

 season as in surface-inhabiting species and that copulation takes place 

 early in the fall. Eggs are said to be laid during the Avinter, l)ut the 

 guides were rather indefinite as to the exact time. 



The smallest specimen collected, a female, is 21 nun. in length; it, as 

 well as the next larger one (26 mm.), differs from the adults in having 

 but one lateral thoracic spine. In a specimen 41 mm. in length all the 

 spines above and in front of the lateral spine are developed. In a 

 specimen 36 mm. long, from Echo River, one accessory spine is present 

 just above the lateral spines, and a few minute granules on the sides of 

 the head, in front of the cervical groove, indicate the patch of spines 

 which is to l)e found in the adult. 



CAMBARUS BARTONI TENEBROSUS, new subspecies. 



7)/7>r.— No. 2231<;. r.S.N.M. Mammoth Cave, Kentuckv. R. E. 

 Call. 



Dldrihiifion. — Known only from the type locality. 



Description. — Compared with the typical C. harton! from the 

 neighborhood of Philadelphia, the carapace is less depressed and with 

 more parallel sides, the areola is longer, the cephalic portion of the 

 carapace is more robust, and the sides of the rostrum are more con- 

 vergent. The antennas are slender and in length exceed the ])od3'. 

 The eyes are reduced in size and the spine armature is much more 

 strongh' developed. There is alwaj^s a small but acute spine on the 

 side of the carapace just behind the cervical groove; the two spines 

 on the upper surface of the distal end of the meros are usually well 

 developed, and the median internal spine of the carpus is large and 

 strong. In addition to these there usually are, in small individuals, 

 well-developed spines at the anterior end of the pbstor])ital ridge and 

 an acute branchiostegian spine. Throughout the entire series exam- 

 ined there is great uniformity in these characters and thev contrast 

 nicel}^ with another small series collected from small surface streams 

 in the neighborhood of the cave. In these the antennas are shorter 

 than the bod}'; the lateral spine of the carapace, even in small indi- 

 viduals, is reduced to a ver}' weak and slender point; the spines on 



