NASA BIDENTATA. 431 
TSOPODA. SPH@ROMIDA. 
NORMALIA, 





sme 
SS 


SSS SSS : 
STR 
NASA BIDENTATA, 
Specific character. Colour ashy, varied with reddish or bluish streaks ; 
sixth segment of the pereion large, overhanging the base of the pleon, which 
has two oval rugose tubercles in the middle. 
Length, about one-third of an inch, ‘‘ Six lines’—Leach. 
Oniscus bidentatus. ADAMS, Trans. Linn. Soe. vol. v. p. 8, t. 2, f. 3, 4. 
Neesa bidentata. Leacu, Dict. Sci. Nat. xii. p. 341. Edinb. Ene. vii. 
p. 405. Trans. Linn. Soc. xi. p. 367. Suppl. Ene. 
Brit. i. p. 427. Samovurnie, Ent. Compend. p. 108. 
Mitne Epwarps, Crust. iii. p. 217. Drsmanrzust, 
Cons. Crust. p. 295, t. 47, f. 2. Wutrs, B. M. Cat. 
Brit. Crust. p. 78. Pop. Hist. Brit. Crust. p. 247, 
pl. xiv. f. 1. Goss, Man. Mar. Zool. 1, 135, fig. 237. 
THis species is at once distinguished from all the other 
British species of the family by the structure of the 
large sixth segment of the body, armed on its hind 
margin in the middle with two long divergent, slightly 
incurved rugose teeth, which completely conceal the 
