GERAPHRYNUS. 49 



material from Dudley that I liave seen. The follownig six, which may he 

 determined by the subjoined key, appear at least to be distinguishable forms : 



a. Carapace as wide as long or wider ; length of the anterior four sternal plates of the 

 opistliosoma much less than that of the posterior three. 

 h. The posterior border of the carapace markedly sinuous, its lateral portions being 

 slightly concave and its median portion convexly produced in the middle line. 



c. Opistliosoma longer and narrower in its posterior portion, the width of its 



penultimate segment about equal to the median length of the carapace ; the 

 posterior border of the seventh and eighth terga distinctly angled avxjnlatiis. 

 c . Opistliosoma shorter and wider in its posterior portion ; the width of the 

 penultimate segment considerably exceeding the median length of the 

 carapace ........ hbuli. 



V . The posterior border of the carapace not markedly .sinuous, either evenly convex 

 or with its lateral portion nearly straight and no rounded median backwardly 

 bulging area. 



d. Posterior border of carapace evenly convex from side to side ; opistliosoma 



short, its greatest width nearly equal to its median length ; no trace of 



tubercles on the anterior terga of the opistliosoma . . efjgintoni. 



iV. Posterior border of carapace with its median area nearly .straight, tians- 



verse, its lateral portions also nearly straight and inclined obliquely inwards 



and backwards from the angles ; opistliosoma long, its greatest width only 



equal to the median length of the anterior eight segments ; a pair of 



tubercles in the middle of the anterior six terga . . tuhercuJatns. 



a . Carapace distinctly longer than wide ; width of the anterior four sternal plates of the 



opistliosoma nearly equal to the length of the posterior three. 



e. Width much more than one-third of the total length ; anterior four terga of 



opistliosoma sinuous ...... angustus. 



e. Width about one-third of the total length ; only the anterior two terga of the 

 opistliosoma sinuous ...... torjiedo. 



Geraphrynus angulatus, sp. nov. Plate III, fig. 2 ; Text-figures 19, 20, 



Carapace closely granular, with median eyes distinct and placed apparently on 

 a tubercle which has a convex anterior border ; its posterior width a little exceeding- 

 its median length ; its posterior border produced and convexly rounded in the 

 middle, its sides slightly concave ; the median area of the carapace about equal to 

 that of the anterior eight tergal plates of the opistliosoma. The median area of the 

 first two terga of the opistliosoma almost obliterated and overlapped by the 

 median backward projection of the carapace ; the posterior border of the third 

 nearly straight ; no large tubercles traceable upon the middle of the anterior six 

 terga ; the median length of the sixth a little exceeding half that of the seventh and 

 a little less than half the median length of the eighth ; the median length of the 

 latter about half that of the ninth, the anterior width of the ninth rather less than 

 two-thirds that of the sixth ; the median length of the ninth about equal to its 



l-r 



