Mr. J. Lycett on the genus Tancredia. 221 



Fryeria. Vent in the middle of the hinder part, in the groove 

 between the mantle and the foot. 



1 . Fryeria pustulosa. Black, with three series of large, unequal, 

 white tubercles on the middle of the back, and with large square 

 white spots containing a tubercle, surrounded by smaller ones, 

 on the edge of the mantle. Phyllidia pustulosa, Riippell, Atlas, 

 Moll. t. 11. f. 1, 1 a. Inhab. Cosseir. Brit. Mus. 



Phjllidia pustulosa, Cuvier, Ann. Mus. v. 266. t. 18. f. 8, may 

 be a bad figure of this species. Cuvier represents the dorsal anus 

 in the other two species, but it is not marked in this, and the 

 colouring somewhat resembles the Museum specimens. 



Thei-e is a considerable diflference in the internal anatomy of 

 this genus, when compared with Cuvier's description of Phyllidia 

 trilineata. 



This genus is named after my excellent friend Mr. J. H. Fryer 

 of Newcastle, who first sent to England the beautiful Chitons, 

 Fissurellce, Purpurte, Murices, and other shells of the coast of 

 Peru; and hence attracted the attention of naturalists and col- 

 lectors to the rich harvest to be made in that country. 



XXII. — Additional Notice of the genus Tancredia {Lycett), 

 Hettangia {Turquem). By John Lycett, Esq.. 



At a meeting of the Cotteswold Naturalists' Club, held July 30, 

 1850, I had the honour to submit a memoir on the Testacea of 

 the middle division of the Inferior Oolite, accompanied by a 

 separate description of a group of small bivalve shells which 

 occur both in that rock and in the Great Oolite. This group I 

 proposed to erect into a genus, to be called Tancredia, a name 

 intended to commemorate a gentleman no longer, unfortunately, 

 a participator in our reunions. The fragility of the small shells 

 which exemplified the genus, together with the coarseness of the 

 investing stone, prevented ray exposing the hinge of the left 

 valve so clearly as could be wished ; it was not therefore figured, 

 and the description of the hinge in that valve was defective ; but 

 the hinge of the right valve, together with the external forms of 

 three species, were faithfully rendered by Mr. Sowerby in the 

 plate which accompanied the memoir. The 'Annals and Maga- 

 zine of Natural History' for December 1850 contained the paper 

 in question, and it was incorporated with the Transactions of the 

 Cotteswold Naturalists' Club. The description of the hinge in 

 the right valve was substantially correct, but owing to an im- 

 perfect knowledge of the form, arising from the valves being 

 always found disunited, the term anterior was employed for 

 posterior, and vice versa. 



It is necessary to revert to these facts with precision, as during 



