18/3.] MR. H. ADAMS ON LAND AND MARINE SHELLS. 209 



genus is described as possessing an elongated lateral tooth, of which 

 there is no trace in either of the species of Thyella. 



Anomalocardta CRASSTCOSTATA,sp.nov. (Plate XXIII. fig. 17-) 



A. testa transversa, subquadrilatera, ventricosa, costis radi- 

 antibus, elevatis, supra planatis ad 22 et lamellis plurimis con- 

 centricis cancellata, pallide fulva, fasciis fulvis inconspicuis con- 

 centrice ornata ; extremitate antica arcuata ad marginem dor- 

 salem angulata ; extremitate postica oblique truncata ; umbo- 

 nibus antemedianis, tutnidis, incurvis, distantibus ; area cardinali 

 lata. 



Long. 25, alt. 20, lat. 20 mill. 



Hab. Persian Gulf {coll. M' Andrew). 



Note. — In the first part of the 'Proceedings' for 1872, at page 

 12, I described a shell from the Isle of Bourbon under the name 

 of Stylodonta (Erepta) bewsheri. Upon since referring to Ferussac's 

 description of his Helix detecta, also from Bourbon, I have come 

 to the conclusion that they are the same species. As H. detecta 

 is the type of the subgenus Rotula, the subgenus Erepta must be 

 restricted to H. stylodon and allied species ; while the very thin mem- 

 branaceous shells, one of which, from Mauritius, was named by me 

 Stylodonta {Rotula) cernica, appear to form a distinct subgenus, 

 for which I would propose the name Caldtvellia, and of which H. 

 phillyrina, Morel., may be considered the type. I would add that 

 the altitude of the shell above mentioned, H. detecta { = bewsheri), 

 which is stated in the description to be 18 mill., is 8 mill. 



I also take the opportunity of changing the name delicatula, 

 given by me to a species of Scala, at page 272 of the 'Proceed- 

 ings' for 1869, to that of tenera, as I find there is already a Scala 

 delicatula of Crosse and Fischer. 



DESCRIPTION OF PLATE XXIII. 



Fig. 1. Coralliophila barclayana, p. 205. 



2. Mitrella dcedala, p. 205. 



3. Zafra purpurea, p. 206. 



4. Odostomia carinata, p. 206. 



5. Amphiperas pulchellus, p. 206. 



6. Collonia munda, p..206. 



7. lAotia bellula, p. 206. 



8. Cyelostrema carinatum, p. 207. 



9. Clanculus pusillus, p. 207. 



10. Minolta variabilis, p. 207. 



11. Helix {Fruticicola) everetti, p. 207. 



12. Bulimus {Drymmus) rawsonis, p. 208. 



13. Corbula pygmwa, p. 208. 



14. Tellidora pellyana, p. 208. 



15. Thyella lamellosa, p. 208. 



16. hargravesi, p. 208. 



17. Anomalocardia crassicostata, p. 209. 



Proc. Zool. Soc— 1873, No. XIV. 14 



