232 BULLETIN 201, UNITED STATES NATIONAL MUSEUM 



Eighth thoracic limb (fig. 99, c) rather long and slightly modified 

 as a fossorial limb, the proximal subjoint of the carpopropodal joint 

 of the endopod being expanded and bearing a row of plumose setae 

 along its anterior outer border. 



Female with two pairs of incubatory lamellae attached to the sev- 

 enth and eighth thoracic limbs. 



First, second, third, and fifth pleopods of the male similar to 

 those of the female, composed of single- jointed flat plates with well- 

 marked setose side lobes. Fourth pleopod of the male (fig. 98, /) 

 biramous, inner ramus of the same form as the remaining pleopods, 

 a simple un jointed plate with a well-marked side lobe, outer ramus 

 composed of three joints terminating in a single strong very stout 

 barbed seta, longer than the combined length of the three joints 

 of the ramus. 



Telson (fig. 98, e) short, quadrangular in shape, only very slightly 

 longer than broad at the base, apex entire and truncate or slightly 

 arcuate, and armed by three small spinules in the center flanked by 

 a pair of stout long spines on each side at the outer angles of the 

 apex; lateral margins armed by two spines, one near the proximal 

 end of the margin, the other at the distal end slightly proximal to 

 the outer of the two large spines at the corners of the apex, so that 

 they appear and may be regarded as part of the apical armature. 



Uropods (fig. 98, d) short and subequal in length without spines 

 on the inner lower margin of the inner pair ; statocyst very small and 

 obviously reduced in size. 



Length of adult specimens of both sexes, 3-3.5 mm. 



Type lot.— Eight males, 11 females, U.S.N.M. No. 81271, from Rio 

 Aranjuez, Puntarenas, Costa Rica. 



Occurrence. — Costa Rica: Rio Aranjuez, Puntarenas, in the holes 

 of a shore crab (Cardisoma crassum Smith) with the larvae of a 

 mosquito {DeinoceHtes pseudes Dyar and Knab), September 12, 1905, 

 collected by F. Knab, 8 males, 11 females, 3 to 3.5 mm., type lot. 



Remarks. — The number of eggs in the brood pouch of a breeding 

 female was only four. 



This species differs from the type and only known other species of 

 the genus, A. cenotensis, in the following points: 



(1) The presence of pigment in the ocular plate. This differ- 

 ence is to be correlated with its different mode of life. A. cenotensis 

 is an underground cave-dwelling species. A. anophelinae is a surface- 

 living form but lives at the bottom of deep crab holes. 



(2) The armature of the telson. A. cenotensis has two median 

 spinules on the apex of the telson and a single large spine at each 

 corner. It apparently has no spines on the lateral margins of the 

 telson at all. 



