BRACHYURA — OXYSTOMATA 



185 



and Latreillia, widely distributed, occur in the Mediterranean. 

 Zatreillopsis from the Pacific. L. petterdi} a magnificent species, 

 with the carapace nearly a foot long, and with very long legs 

 like a Spider-crab, has been dredged from 800 fathoms east of 

 Sydney, New South Wales. 



Tribe 2. Oxystomata. 



This group comprises Crabs whose carapace is more or less 

 circular, while the mouth, instead of being square as in the 

 remaining Brachyura, is triangular with the apex pointing for- 

 ward, and the third maxillipedes are not expanded into the 

 flattened, lid-like structures found in other Crabs. There is the 

 same tendency in some of the genera for the posterior thoracic 

 limbs to be reduced and carried dorsally, as in the Galatheidae 

 and Dromiacea. The well-known Bori2)pe from the Mediterranean 

 has this feature, and frequently carries an empty shell upon its 

 back, and Cymonomus" presents the same peculiarity. 



Gymonomus granulatus (Fig. 127) is an abyssal form that has 



Fig. 127. — Gymonomxis granulatus, x 1. A.l, A.2, 1st and 2nd antennae ; E, eye- 

 stalk ; S, extra-orbital spine of carapace. (After Lankester. ) 



been dredged from the Mediterranean and North Atlantic, in which 

 the eye-stalks are curiously tuberculated, and the ommatidia of 



1 M'Cullocli, Mec. Australian Mus. vi. part 5, 1907, p. 353. 

 2 Lankester, Quart. J. Micr. Sci. .xlvii., 1903, p. 439. 



