170 Prof. F. M'Coy on the Classification of 



feet from the Anomura to the Brachyura. In the general form 

 of the carapace, of the rostrum, in the completeness and form of 

 the orbits with the two fissures in their upper edge, it so exactly 

 resembles Corystes as to have even deceived Dr. Leach, the first 

 crustaceologist of his day (see Mantell's Geol. of Sussex, p. 97). 

 I first suspected its anomurous nature from observing the faint 

 sulcus dividing the branchial regions as we so commonly see in 

 the short-tailed Anomura, and subsequently was gratified by the 

 Woodwardian Inspectors with the sight of a little specimen of 

 the N. Mantelli (M'Coy) in the old cabinet left by Woodward 

 to the University of Cambridge, showing the chelse and bases of 

 all the feet, proving the posterior pair to be abruptly smaller than 

 the preceding ones and elevated above them, and completely 

 establishing the position of the genus : curiously enough, the 

 entry of this specimen in Woodward's MS. Catalogue indicates the 

 same analogy with the recent form which Dr. Leach pointed out 

 so many years afterwards. This genus includes the " Corystes 

 of Leach and Mantell (Geol. Suss. p. 129. figs. 9 & 10), also the 

 species figs. 13, 15, 16 of the same plate, and the " species of a 

 new genus allied to Arcania" figs. 7, 8, 14 of the same plate, 

 which is also the Orithya Bechei of Deslongchamps (Mem, de la 

 Soc. Lin. de Normandie). Dr. Mantell in the above plate, fig. 15, 

 shows a large joint in the abdomen below the fifth large one ; the 

 specimen of the tail which I have seen is broken before the end 

 of the fifth joint, so that I have no independent authority for the 

 sixth joint or its mode of junction with the fifth, or whether the 

 supplementary side pieces occur between them. 



Notopocorystes Mantelli (M'Coy). 



Sp. Char. Greatest width of carapace (at base of gastric region) 

 one-fifth less than the length ; three strong teeth on the an- 

 terolateral margin, the middle one largest, placed at the end 

 of the nuchal sulcus, the lower one between the first and the 

 end of the faint branchial sulcus, at the end of which a fourth 

 small tooth is found ; gastric region with a narrow mesial ridge 

 from the rostrum bearing three small tubercles on its posterior 

 half; each side of this region has a row of three tubercles 

 running parallel with the gastric or nuchal furrow, the space 

 between them being about equal to their distance from that 

 furrow ; behind the inner tubercles of each row is one rather 

 smaller ; the genital region bears one elongate tubercle in the 

 middle ; cardiac and intestinal regions with a mesial ridge, the 

 former bearing two large and the latter two small tubercles ; 

 branchial regions with an obtuse boss close to their upper in- 

 ternal angle, and two equidistant tubercles on each side in an 

 oblique line to the second marginal tooth close under the 



