200 CLASS CRUSTACEA. 



In some the crustaceous buckler is preceded by a small 

 plate, more or less triangular, situated above the articulation, 

 bearing the middle antennas and the eyes, covers only the an- 

 terior portion of the thorax, and does not fold underneath 

 laterally. The articulation serves as a peduncle to the mid- 

 dle antennae, as well as to the ocular pedicles, and the exter- 

 nal sides of the end of the abdomen are uncovered. 



Sometimes the body is almost semi-cylindrical, with the last 

 segment rounded, denticulated or spiny at the posterior edge. 

 The lateral appendages of the last six feet are in the form of 

 a stylet. 



Squilla, proper, Latr., 



Have, along the internal side of the last articulation but one 

 of the two large claws, a very narrow groove, denticulated on 

 one of its edges, spiny on the other, and the following ar- 

 ticulation, or talon, in the form of a reaping-hook, and most 

 frequently denticulated. {Cancer mantis, Linn.) 



GONODACTYLUS, Latr. 



The groove of the last articulation but one of the large 

 claws is widened at its extremity, and presents neither denti- 

 culations nor spines. The talon is bellied out into the form 

 of a knot towards its base, and afterwards terminates in a 

 compressed point, straight, or but little curved. All the 

 species are exotic. {Squilla scyllarus, Fab.) 



Sometimes the body is very narrow and depressed, with 

 the last segment, almost square, entire, without denticulations 

 or spines. The lateral appendage of the last six feet is in 

 the form of a palette, almost orbicular, and jutting out a little. 

 The antennae and feet are shorter than in the preceding. The 

 last articulation but one of the large claws is furnished at the 

 internal edge with very numerous hairs, in the form of little 

 spines. The talon is like a reaping-hook. 



