62 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I3I 



fills the cavity of the snail shell ; pleopods are present generally on the 

 left side only, but the uropods are strong, recurved appendages evi- 

 dently serving to secure the crab in its house. 



STOMATOPODA 



The stomatopods are an individualistic group of malacostracans 

 having some relatively primitive features in combination with so many 

 structural specializations that it is difficult to give them a definite 

 place in taxonomy. The head of the adult animal (fig. 24 G), pro- 

 jecting from beneath a small rostral lobe of the carapace, has a com- 

 plex structure not found in any other crustacean. The short, narrow 

 carapace covers only the gnathal region and the first four thoracic 

 segments. The other four free segments of the thorax are symmetri- 

 cal with the large abdomen, and appear to be a part of it except for 

 the leglike appendages borne on the last three. The limbs of the first, 

 third, fourth, and fifth thoracic segments are turned forward and each 

 bears a small apical chela; but those of the second segment {2L) are 

 huge raptorial organs in which the terminal segments are long, strongly 

 toothed claws, each closing tightly against the penultimate segment, 

 giving the stomatopod its likeness to the insect praying mantis (which 

 is not responsible for its name). The large abdomen has five pairs of 

 pleopods, and the stomatopod gills are borne on the pleopods. The 

 uropods are large, biramous appendages ; the telson is a broad spiny 

 plate. 



The adult stomatopods are mostly littoral in their habits. Though 

 they swim freely, they live principally in burrows in the sand or mud 

 of the bottom. The females lay their eggs in a mass beneath the fore 

 part of the body, where they are held between the raptorial legs by 

 the four small chelate legs of the thorax. The eggs are carried in this 

 manner until the young larvae emerge, a period said by Giesbrecht 

 (1910) to last for 10 or 11 weeks. 



The young stomatopods are hatched in two different larval forms, 

 which seem to have no developmental relation to each other. Our 

 best source of information on tlie larval stages will be Giesbrecht's 

 (1910) elaborate monograph on Mediterranean species. Gurney 

 (1946) gives descriptions and good illustrations of various stomato- 

 pod larvae, but no full account of the life history of any one species. 

 Alikunhi (1952) describes and figures particularly the last-stage 

 larvae of Indian species. 



The simpler first-stage larval form pertains to species of Lysio- 

 sqiiilla and Coronida, and is termed by Giesbrecht an antesoea. This 



