ORDER 8TOMAPODA ; PHYLLOSOMA, OR GLASS-CRAB. 25? 



and these are directed towards the mouth, in such a manner as 

 to hold the prey again'st it, in the most efficient manner. The 

 three posterior pairs of legs, which are attached to the annulated 

 (or ringed) portion of the thorax (c), are furnished with a brush 

 instead of a hook at their extremities, and more resemble the ab- 

 dominal swimming legs. The tail is expanded into a broad fin. 

 Thus we see that the locomotive apparatus of this animal is 

 partly adapted for prehension, and partly for natation (or swim- 

 ming), and not at all for walking. This species is probably the 

 largest of the Order ; its length being about seven inches. It is 

 common in the Mediterranean. 



866. To this Order also belongs a very curious genus, the Phyl- 

 losoma, or Glass-Crab. Its scientific name, which means leaf- 

 bodied, as well as its common designation, refer to the remarkable 

 peculiarity of structure by which it is distinguished j the whole 

 body being flattened like a leaf, and almost as transparent as glass. 

 It is composed of a large oval plate, which represents the head, 

 and bears the two eyes, mounted on long footstalks, at its anterior 

 extremity ; of a second plate, in part covered by the preceding, 

 and bearing the thoracic legs; and of an abdomen which is 

 always short, and sometimes undeveloped. The legs, six in 

 number, are very long and slender ; they are bifid, like those 

 of the Mysis ; and are adapted for swimming only. These curi- 

 ous creatures are inhabitants of the tropical parts of the Atlantic 

 and Eastern Oceans. 



867. It is scarcely possible to avoid being struck by the analogy 

 presented by this Order to the Orthoptera among Insects. The 

 resemblance of the Squilla to the Mantis has already been noticed ; 

 and the correspondence of the Phyllosoma to the leaf-like species 

 of the same order ( 729), is scarcely less remarkable. We may 

 also point out the many resemblances between the Decapod Crus- 

 tacea and the Coleopterous Insects. They occupy a corresponding 

 position, in being at the head of the mandibulate series of their re- 

 spective classes ; they are both also pre-eminent in regard to the hard- 

 ness of their integuments ; and in bojfch there is an adaptation of the 

 extremities for walking, rather than for swimming or flying which 

 are actions analogous to each other (ANIM. PHYSIOL., 663). 



