110 PROCEEDINGS OF THE ACADEMY OP 



defined and crenulate. The second joint has on its anterior face one or two 

 crenate ridges ; its posterior margin is rounded off. The hands are large, and 

 have only their superior and inferior edges distinctly crenate. The fingers are 

 robust and moderately long, with their opposing margins armed with a single 

 row of teeth, with larger ones at regular intervals on one side of their distal 

 portion. The feet are compressed. The tail is rather robust. The first 

 three joints have their superior and supero lateral ridges sharply serrate, and 

 terminating posteriorly in a spine. In the fourth they are the same, except 

 that the terminal spinule of the supero-lateral crest is wanting. The first 

 four joints have infero lateral and inferior crests, the former mostly distinctly, 

 the latter indistinctly (excepting on the posterior segment) serrulate. The 

 penultimate articulation is long, and armed with distinctly serrulate supero- 

 lateral, infero-lateral crests, as well as a single median inferior; and on its an- 

 terior half, central lateral ridges. Its form is that of a parallelopipedon 

 thinned at its two extremities. The superior surface of the last joint is trian- 

 gular and complanate ; the inferior is convex. The sting is very long, slender, 

 and gracefully curved. The sternal plate is pentangular. 



Length of body, tf 10 lines, $> 12 lines: of tail, tf 16 lines, $ 14 lines. 



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



B. SPIMGERtrS. 



B. dilute olivaceo-fulvus, fusco vitatus ; cephalothorace antico hand emargi- 

 nato, medio canaliculato ; oculis lateralibus in serie curvata positis ; palpi 

 modice robustis, marginibus valde crenulatis ; manibus nonnihil tumidis, 

 lineis elevatis obsoletis ; digitis nonnihil elongatis, modice curvatis, margini- 

 bus opponentibus et dentatis et crenulatis ; abdominibus mediis nonnihil 

 carinatis ; cauda modice breve, robustissima, lineis elevatis denticulatis ; spi- 

 culo sine spinulo basali ; pectinis dentibus 20 25. 



The color of this species varies ; generally each abdominal plate has a dark 

 brown v or w shaped marking, forming a continuous stripe on each side. This 

 is obsolete on the cephalothorax. But this distinctness of pattern is often 

 lost, and the whole body involved in an olive-brown tint. The palpi closely 

 resemble those of B. boteus, but have the hand not so large, and the facets 

 and elevated lines not so strongly pronounced. The opposing margins of the 

 fingers resemble those of that species in their armature, but want the wavy 

 outline. On each side of the abdominal median line are numerous small black 

 tubercles, so arranged as to form more or less prominent ridges. There is 

 also a series of these on the posterior border of each of the abdominal scuta. 

 The legs and tail are of a dirty yellow color. The anterior four caudal joints 

 are short and very robust, the breadth of the first three often equalling their 

 length. These four joints are provided with denticulate superior and supero- 

 lateral crests. In the anterior three these are of nearly the same length, and 

 terminate distally in a small spine. In the fourth, the dorsal is only two- 

 thirds the length of the other raised line, and the joint is then scooped out to 

 the level of the latter, which does not end in a spine. On the first four 

 articulations the middle lateral crests are almost entirely obsolete. On the 

 fifth they are more strongly pronounced. This joint is much more elongate 

 than the others. Its supero-lateral crests are not so strongly denticulate 

 as those of the others, and have no spine at their distal extremity. The in- 

 fero-lateral and inferior crest exist on the first four joints as four black, oc- 

 casionally somewhat obsolete, ridges, but are not crenulate. On the fifth 

 both the inferior-lateral and the single median-inferior crests are denticulate. 

 The sixth caudal joint is somewhat ovate, flattened above, and without ridges. 

 On the lower surface there exists a faint mesial groove. The sting is slender 

 and strongly curved. 



Length of body, tf 9 one i ncn > f * a ^> ? one inch, two lines ; $ one 

 inch, four lines. 



Hab. Texas. Smithsonian Museum. 



[April, 



