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MODERN SYSTEM. 



Subclass II. MALACOSTRACA. 



A very valuable work is now publishing by Dr. Leach, in quarto, and 

 illustrated with highly finished engravings, entitled, ]VI.\LACosTR.ic.\. 

 PoDOPiiTH.'vLMA Britanni^, in which the whole of the indigenous spe- 

 cies hitherto discovered of this subclass are figured. It is necessary to 

 state that this gentleman has spared neither pains nor expense to ren- 

 der the work complete, having with unexampled zeal and perseverance 

 amassed together one of the finest collections ever formed, which is, 

 with the remainder of his cabinet, consisting of insects, shells, &c. de- 

 posited in the British Museum, and, under certain restrictions, may 

 always be consulted by students of Zoology. 



Legion I. PODOPHTHAL M A. 



" The Malacoatmca Podophthalma include those animals which, iu 

 common language, are denominated Crabs, Lobsters^ Cray-fish, Prawns, 

 Pandals, and .Shrimps, all of which have the power of reproducing their 

 claws when they are lost." 



Order I. BRACHYURA. 



A. Abdomen of the male Jive-jointed, the middle joint longest ; of the 

 female seven-jointed. Anterior pair of legs didactyle. {Shell trun- 

 cate behind. Tzco anterior legs of the male elongate, of the female 

 moderate.) 



Fam. I. CoRYSTiDi. Leach. 



Antenna long, ciliated on each side. 



Genus 1. CORYSTES. Lutr., Leach. 

 External antennte longer than the body; the third segment composed of 

 elongate, cylindric joints: external double palpiwhh the external foot- 

 stalk narrow; the second joint largest, having its internal side deeply 

 emarginate : anterior pair of legs, of the male twice the length of the 

 body, subcylindric, the hand gradually somewhat thicker and some- 

 what compressed; of the female, of the length of the body, with a 

 compressed hand : other legs with tibia; and tarsi of equal length : 

 claws elongate, straight, acute, and longitudinally sulcated: abdomen, 

 of the male, with the first joint linear-transverse; the second longer, 

 and produced on each side ; third, nearly equally quadrate; the fourth 

 transverse, and narrower than the third; the fifth narrower, nearly 

 triangular, with the tip rounded ; of the female, with six joints trans- 

 verse, arcuated in front; seventh triangular, with the apex rounded : 

 shell oblong-ovate, anteriorly slightly rosti-ated, behind margined : 



