THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



[SECOND SERIES.] 

 No. 21. SEPTEMBER 1849. 



XIX. — On the Classification of some British Fossil Crustacea^ with 

 Notices of new Forms in the University Collection at Cambridge. 

 By Frederick M^Coy, Professor of Geology and Mineralogy 

 in Queen's College, Belfast. 



The class Crustacea having received less attention from British 

 palaeontologists than perhaps any other of similar importance, I 

 have put together in the following pages a few observations I 

 have been able to make on the examples in the collection of the 

 University of Cambridge, as well as on a great number of speci- 

 mens of the same species, for the most part finely preserved, 

 lent me by various friends to render my observations as perfect 

 as possible. I have given descriptions of some of the best-marked 

 new species, also of some new genera ; I have endeavoured to refer 

 some others, hitherto improperly placed in recent genera, to the 

 various fossil genera established by foreign writers for cognate 

 forms, and have ventured a few suggestions on the classification 

 and systematic position of some of the groups. 



Class CRUSTACEA. 



Ord. PoDOPHTHALMA. Tribe Decapoda. 



{Brachyura.) 



Of this the most highly organized group of Crustacea, I believe 

 the following genera have been quoted from British rocks with- 

 out sufficient authority: viz. 1. Zantho (Leach); this has been 

 quoted with doubt by Desmarest, Bronn, &c. from the London 

 clay ; I have ascertained that the Crustacea referred to are of an 

 extinct genus, more nearly related to Pilumnus than to Zantho j 

 which I have named Zanthopsis. 2. Orithya (Fabr.) : M. Des- 

 longchamps referred with doubt a crustacean originally disco- 

 vered by Sir Henry de la Beche in the greensand of Lyme Regis, 

 to this recent genus of natatory Brachyura ; I find however that 

 the species referred to (O. Labechii of Desl. Mem. de la Soc. Linn. 



Ann. ^ Mag. N. Hist. Ser. 2. Vol. iv. 11 



