352 SQUILLA MANTIS. 



plate semiovate ; the middle portion of the carapace has a 

 longitudinal median crest, which bifurcates anteriorly, and it 

 is separated from the lateral pieces by a deep groove, which 

 is continued transversely to separate the posterior portion ; 

 the lateral pieces have on each side two raised lines or 

 crests, the outermost of which extends back to near the 

 posterior margin. The claws very long and robust ; the 

 last joint furnished with six sharp, slightly curved teeth, 

 inclusive of the extremity ; the next joint with a deep 

 groove for the reception of the last when closed, and the 

 inferior margin of the groove is denticulated, and furnished 

 with three moveable teeth at the base. The three pos- 

 terior segments of the thorax with four crests. The ab- 

 domen is very broad and thick, broader and flatter towards 

 the extremity, and having eight distinct crests, including 

 the lateral margin of the segments ; the two middle ones 

 are nearer to each other than the others, and on the sixth 

 segment terminate each in a sharp spine. The last abdo- 

 minal segment (middle lobe of the tail) about as long as it 

 is broad, furnished with a high median crest, terminating in 

 a tubercle, at a short distance from the margin the surface 

 generally marked with a number of impressed points, ar- 

 ranged in curved lines. The margin is raised and thickened, 

 and furnished with two pairs of lateral spines or tubercles, 

 and there are two pairs of sharp strong spines on the ante- 

 rior portion, with numerous small denticuli between them. 

 The laminar prolongation of the basilary joint of the ap- 

 pendages to the sixth segment extends backwards as far as 

 the external caudal scale, and is furnished with two very 

 strong pointed horns. The first joint of the outer caudal 

 lamina is strong and thick, and furnished, on its outer 

 margin, with several strong spines which appear to be 

 moveable. 



