ORDER STOMAPODA. 199 



body, enclosing a good part of the heart, and serving as an 



attachment for the respiratory organs, cannot, considering this 



relation, be assiroilated to that portion of the body termed 



tail in the decapods ; it is an abdomen, properly so called. 



Its last segment but one has, on each side, a fin, similarly 



composed as that of the tail in the macrouri, but often armed, 



as well as the last segment or intermediate piece, with spines 



or teeth. 



We shall divide the stomapods into two families ; in the 



first, that of 



Unipeltata, 



The testa forms but a single buckler, in the shape of an elon- 

 gated quadrilateral figure, usually Mddened, and free behind, 

 covering the head, with the exception of the eyes and antennae 

 (which are borne on a common and anterior articulation), and 

 the first segments at least of the thorax. Its anterior extre- 

 mity is terminated in a point, or is preceded by a small plate, 

 finishing in a similar manner. All the jaw-feet, the second 

 of which are very large, and the four anterior feet, are very 

 much approximated to the mouth, on two lines, converging, 

 inferiorly, and are formed like claws, with a single finger or 

 hook, mobile and folded. If we except the second feet, all 

 these organs have, externally, at their origin, a small pedi- 

 cled bladder. The other feet, six in number, and the third 

 articulation of which carries laterally and at its base an ap- 

 pendage, are linear, terminated by a brush, and simply nata- 

 tory. The lateral antennae have a scale at their base, and the 

 stem of the intermediate is formed of three threads. The 

 body is narrow and elongated, and the ocular peduncles are 

 always short. 



This family is composed of a single genus, that of 



Squilla, Fab., 

 Which we thus divide : 



