NATURAL SCIENCES OF PHILADELPHIA. 109 



Length of body, 1 5-8 inches : of tail, 2 5-S inches. 



Hab. Lower California. J. Xantus de Vesey. Smithsonian Museum. 



B. EJIARGINATICEPS. 



B. olivaceo-fulvus ; palpi, pedibus caudaque longe pilosis ; cephalo- 

 tborace antico late et profundissime emarginato, sed alibi, B. hirsuti illo 

 simillimo ; palpibus crassibus ; marginibus nonnihil crenulatis ; manibus 

 modice tumidis, obsolete septemplicatis, marginibus anticis posticisque tuber- 

 culatis ; pectinis dentibus 30 ; abiomiue nonuib.il lcevi, medio baud carinato ; 

 spiculo sine spinulo basali. 



Tbe color of our single specimen is an olive-yellow tint, witb a very dark 

 crescentic blotcb at the position of the median eyes. But in this pattern it 

 does not differ from some individuals of the preceding species. The cephala- 

 thorax differs from that of B. hirmtus only in one character : In its anterior 

 border is a very large emargination, which reaches about one-third of the dis- 

 tance to the melian eyes. The abdomen is precisely like the preceding 

 species. The tail is perhaps a little less massive. But it also so closely re- 

 sembles that of B. hirsutus the description of one will answer for the other. 



Length of body, 1 5-8 inches : of tail, 2 5-8 inches. 



Lower California. J. Xantus de Vesey. Smithsonian Museum. 



B. EtTSTHEXURA. 



B. aurantiaco-brunneus ; dorso tuberculis minimis asperato ; cepbalotho- 

 race hand emarginato, medio canaliculato ; oculis lateralibus utrinque in serie 

 curvata dispositis ; palpi gracilibus longis, longe sparse pilosis ; manibus 

 parvis, baud tumidis, subcylindraceis ; cauda modice longa, percrassa ; spi- 

 culo brevissimo, valde curvato, sine spinulo basali ; pectinis dentibus fere 17. 



The surface of the cephalothorax is rough and uneven. The hands are 

 very small and smooth, with some traces of the eight facets so distinct in E. 

 punctipalpi. The fingers are about as long as the hand, rather slender, with 

 their opposing margins armed with a row of very sharp, minute teeth, and 

 much larger ones placed at intervals on one side of their distal portion. The 

 legs are somewhat compressed ; very long and slender. The tail, when com- 

 pared with the boly, is very heavy. On the first four joints the superior and 

 supero lateral crests are alone serrulate. The superior terminates in a spine, 

 feebly pronounced on the fourth article. The inferior and infero lateral crests 

 are distinct, but not crenulate. The penultimate segment has well-marked, 

 but not crenate, supero and infero lateral ridges, besides a single median infe- 

 rior and median lateral on their proximal portion. The terminal joint resembles 

 that of B. punctipalpi, but is much larger and thicker, and not so prolonged 

 posteriorly. Sternal plate pentangular. 



Length of body, $ 7 lines : of tail, tf 13 lines. 



Hob. Cape St. Lucas. J. Xantus de Vesey. Smithsonian Museum. 



B. PUNCTIPALPI. 



B. aurantiaco-brunneus ; dorso tuberculis minimis asperato ; cephalothorace 

 medio canaliculato, antico nonnihil emarginato ; palpi dense minutissime 

 punctatis, nonnihil robustis ; manibus magnis, tumidis, octo faciebus indis- 

 tincte instructis ? cauda modice longa et crasse ; articulo penultimo longo, 

 ultimo parvo, supra complanato ; spiculo gracillimo, valde elongato, gradatim 

 curvato, sine spinulo basali ; pectinis dentibus fere 20. 



All of our specimens are immaculate ; some of them shade off in color to- 

 wards an olive. The lateral eyes, three in number, are generally arranged in 

 a slightly, but occasionally in a strongly curved line. The cephalothorax, 

 and, indeed, the whole dorsum is roughened by very numerous minute tuber- 

 cles. The scuta are more or less distinctly medianly keeled. The joints of 

 the palpi are irregularly parallelopipedal, with their margins mostly well- 



1863.] 



