ZOOLOGY OF FERNANDO NORONHA. 



525 



surface almost smooth, with a few small tubercles near the upper 

 and under margins. Upper margin compressed into a serrated 

 keel; under margin also serrated. Anterior margin of hand 

 nearly at right angles to the axis of the pollex. Pollex upturned 

 at the apex, furnished on its occludent margin with a tooth 

 which closes behind the tooth of the dactylopodite. Upper 

 margin of dactylopodite serrated. 



Fourth and fifth pairs of limbs resembling each other in being 

 slender and elongated, in having the propodite furnished below 

 with a series of fine spines and consisting of three segments, and 

 in having the dactylopodite bifid. But whereas the propodite of 

 the fourth pair consists of five segments, the propodite of the fifth 

 pair consists of but three. The number of divisions of these 

 segments, however, appears to vary upon the two sides. 



Abdominal tergites smooth above ; lateral portions narrowed, 

 somewhat pointed, and with margins more or less spined. 



The outer and inner lamellae o£ appendages of the sixth 

 abdominal somite with a median longitudinal crest, serrate 

 exterior margin, and fringed inner margin. Outer margin of 

 inner lamella furnished below with a stronger tooth. 



Telson with converging lateral margins, rounded posterior 

 margin; each lateral margin furnished with a central tooth; 

 posterior margin furnished with three teeth, one on each side 

 and one in the middle. Upper surface of telson marked with two 

 longitudinal crests, each of which bears three spines arranged 

 longitudinally; the depression between the crests furnished proxi- 

 mally with four spines in two longitudinal series. Base of 

 telson bearing on each side one marginal spine. 



Two specimens. 



Length from apex of rostrum to posterior margin of telson 

 13 millim. ; total length of upper surface of carapace (including 

 rostrum) 5| millim. ; length of manus and pollex of third pair of 

 feet 8 millim. 



This species seems to difi'er from >S'^. crassimanus, Richters, 

 in the possession of a greater number of teeth upon the rostrum 

 and in the absence of a crest upon the abdominal tergites. 



The three species which hitherto have, so far as 1 am aware, 

 composed the genus were taken at Touquets (Mauritius). 



