150 



CORYSTID.E. 



it occurs in Mr. Bean"'s collection at Scarborongli. In the 

 Fritli of Forth it is mentioned by Mr. Gooclsir as being- 

 very rare. Mr. Thompson records its occurrence as an 

 Irish si3ecles in Roundstone Bay, Connemara ; Mr. Ball 

 found several on the beach at Portmavnoch after a storm ; 

 and Captain Portlock obtained it " by deep dredging in 

 Belfast Bay, in the course of the Ordnance Survey.''* 



The vignette is an illustration of the sign Cancer, from 

 a thirteenth century drawing, contained in the Prayer- 

 book of Queen Mary in the British Museum. 



* Thompson, Ann. and Mag. Nat. Hist. vol. x. p. 2f)5. 



