52 



MEMOIES OF THE NATIONAL ACADEMY OP SCIENCES. 



either edge ; the spines are all tipped with long bristles, bent towards and crossing those of the opposite row. The 

 male *organ is cylindrical, without joint or median swelling, as thick as the coxse, not chitiuous, bearing at tip a few 

 flue hairs ; when fully protruded it equals one-third of the body in length. The abdomen shows but four narrow and 

 one conical terminal segment beyond the cephalothoracic shield. The conical eminence at the anterior border of the 

 dorsum, between the first pair of legs, is without trace of ocelli. Length without appendages, 2 mm = .08 inch ; 

 longest leg, 18 mm == .72 inch. 



Two specimens in alcohol from Martha's Vineyard, in the Mammoth Cave. 



Fig. 14. — Phalangodes armata : a, claw of anterior tarsus ; 6, claws of posterior tarsi ; c, enlarged ten times (after Hn board). 



Remarks. — This form, though living in Mammoth and adjoining smaller caves, and sometimes 

 occurring near daylight, seems to undergo almost no variation, either as regards the absence of 

 any traces of eyes or the remarkable length of legs. It is the extreme in a series of forms, including 

 Phalangodes flavescens, var. coeca, weyerensis, and the terricolous P. spinifera, with the very stout, 

 short-legged P. robusta. Without much doubt P. armata has been derived from a form like P. 

 spinifera; or from an earlier terricolous species, from which both diverged. 



PHALANaoDES SPINIFERA, n. sp. Plate XIII, figs. 2, 2a, 2b, 2c. 



One female. Body rather broad and stout; more contracted on the sides behind the inter- 

 ocellar spine than in P. robusta. Cephalothorax widening considerably behind the hinder edge; 

 it is two-thirds as long as the body. The eyes are considerably smaller than in P. robusta, black, 

 and placed unusually far apart; between them is a conical projection ending in a high, sharp 

 prolonged spine. There are five abdominal segments seen from above, the fifth narrow, conical 

 minute. The surface of the cephalothorax is rough, with sharp granulations, and the hind edge 

 with that of the succeeding segments, are adorned with a row of sharp spines, the median ones 

 largest, those on the fourth segment being more numerous, large, and sharp, with a group of about 

 five large ones of unequal size on each side of the body. 



The chelicerae are 2.5 mm long, much longer and slenderer than in P. robusta; but closely like 

 those of P. armata from Mammoth Cave, the first joint being similarly contracted toward the base; 



* This appears to be the ovipositor of the female. 



