STOMATOPODA. 471 



The sub-order Stomatopoda, with which formerly the Schizopoda, 

 the genus Leucifer and the Phyllosomata (which are now known to 

 be the larvae of Scyllarus and Palinurus) were united, is confined 

 at the present day to the small and well-defined group of forms 

 included in the Squillidce. 



They are Thoracostraca of considerable size and of elongated 

 shape, with a broad, well-developed abdomen, which is much more 

 extensive than the anterior part of the body and terminates in an 

 extraordinarily large caudal fin. The cephalo-thoracic shield, which 

 is formed of comparatively soft integument, is short and leaves 

 at least the three large posterior thoracic segments to which the 

 biramous swimming feet belong quite uncovered. The short segments 

 of the maxillipeds also are not fused with the carapace. 



Appendages. The anterior part of the head with the eyes and 

 antennae is movable, and the ventral portions of the following 

 segments covered by the cephalo-thoracic shield are capable of 

 limited movements upon one another (fig. 369). The anterior 



A' 



FIGL 300. Squilla mantis. A', J", antennae ; Kf, Kf, the anterior maxillipeds on the 

 cephalothorax ; B', B", B"', the three pairs of biramous legs. 



internal antennae consist of a long three-jointed shaft, bearing three 

 multiarticulate flagella. The second pair of antennae has a large 

 scale on the outer side of the multiarticulate flagellum (fig. 369). 

 The mandibles, which are placed far back, are provided with a slender 

 three-jointed palp. The maxillae are relatively small and weak. 

 The five following pairs of pediform appendages are crowded 

 together close to the mouth, and on this account have been appro- 

 priately described as oral feet. They all bear at their base a 

 discoidal plate, which, in the case of the two anterior pairs, attains a 

 considerable size. The anterior pair alone (first maxilliped) is 

 slender and palpiform ; it ends, however, in a small chela, which 

 serves to seize the prey. The chela in this and all the other 

 maxillipeds of the Stomatopoda is formed by the terminal joint 

 turning back and biting on the penultimate joint. The maxillipeds 



