CRUST^OE A^. 



MAIID^. 

 LIBININ^. 



LIBINIA SEMIZONALE, Streets, n. sp. 



Carapace pyriform ; regions distinctly marked ; surface shining, un- 

 even, and shortly pubescent in places; pubescence more marked ante- 

 riorly ; spinous. The arrangement of the spines is as follows : — eight in 

 the median line of the body, placed, four on the gastric region, one on 

 the genital, two on the cardiac, and one on the intestinal ; on the ante- 

 rior portion of the ga.stric region are two other spines, arranged trans- 

 versely, in a line with the first one of the longitudinal series ; so that all 

 the spines of this region form the letter T; on the hepatic region are 

 two spines, placed one above the other; immediately beneath these, on 

 the lateral line, is another (on the left side there were two); the spines 

 Ijl on the hepatic region, with those on the lateral line and the transverse 

 row on the gastric region, taken together form a semicircle across the 

 anterior portion of the carapace ; sub-hepatic spines two, the anterior of 

 which is the larger; there is another under the lateral line posterior to a 

 sulcus separating the hepatic and branchial regions; four on the middle 

 of the branchial region, inclosing a regular diamond-shaped space; 

 another small spine on the upper part of the same region, on the edge 

 of the depression separating it from the cardiac region; finally, there 

 is an elevation, or a faint trace of a spine, on the posterior part of the 

 branchial region. 



Eostrum prominent, broad ; broadest at the base, and slightly con- 

 verging to the points; directed upward at an angle with the body ; con- 

 vex above and densely pubescent ; the entire under surface deeply ex- 

 cavated ; its apex obliquely truncated above, producing, by reason of 

 its hollow under surface, two points, the outer surfaces of which are 



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