REPORT ON THE GASTEROPODA. 453 



Naiica pyriformis, Recluz, Proc. ZooL Soc. Lond., 1843, p. 211, sp. 21. 



„ mamilla, Philippi, Conch. Cab. (ed. Kiister), p. 31, sp. 27, pL iv. figs. 7, 8, and (as Natica 

 pyriformis), p. 60, sp. 64, pi. ix. fig. 8. 



„ „ Eydoux and Souleyet, " Bonite," vol. ii. p. 576, No. 172, pL xxxv. figs. 16, 17. 



Nerita mamilla, Hanley, Ipsa Linn. Conch., pp. 396, 542. 

 Natica mamilla, Reeve, Conch. Icon., vol. ix. pi. vii. fig. 27. 



,, „ Deshayes, Moll. Reunion, p. 79, No. 230. 



„ „ Sowerby, Thes. Conch., pts. 39, 40, p. 85, sp. 58, pi. cccclvi. (iii. Gen.), figs. 28-30. 



„ „ Issel, Mai. Mar Rosso, p. 186, No. 457, p. 285, No. 177. 



„ „ v. Martens, Moll. Mauritius, &c, p. 276. 



Tiber mamilla, Dunker, Index Moll. Mar. Japon., p. 62. 



September 9, 1874. Off Albany Island, Cape York, Torres Straits. 3 to 42 fathoms. 



Habitat, — The whole Indian Ocean from the African Coast and Red Sea to Ceylon, 

 the Nicobars, and the Malay Archipelago (v. Martens). 



Fossil. — On shores of Eed Sea (Issel). 



As this species has often been confounded with others, it may be useful to say that (apart from 

 other obvious differences), it is distinguished from Natica aurantia, Lam., by its minute, delicate, 

 depressed, and black apex, and from Natica porcellana, d'Orb., to which, in these respects, it lies 

 much nearer, by the apes being still smaller, by the much slower increase of the whorls, and by its 

 entirely closed umbilicus, which in that species is always half open. On careful examination of 

 Recluz's type of Natica pyriformis in the British Museum, I satisfied myself that, as Philippi suspected, 

 this was only a young form of Natica mamilla. The " parallele Furche " " am Rande der Spindel," 

 which made Philippi hesitate, is a mere feature of immaturity filled up in the older shell. Mr E. A. 

 Smith fully shared my opinion of this species. 



27. Natica {Mamma) f)orcellana, d'Orbignj r . 



Natica porcellana, d'Orbigny, Moll. Canaries, "Webb and Berthelot, p. 84, pL vi. figs. 27, 28. 

 „ „ Philippi, Conch. Cab. (ed. Kiister), p. 62, sp. 68, pi. x. fig. 4. 



„ ,, Reeve, Conch. Icon., vol. ix. pi. xxiii. fig. 102. 



„ ,, Seguenza, Formaz. Terz. Calabria, p. 354. 



„ „ Sowerby, Thes. Conch., pts. 39, 40, p. 89, sp. 82, pi. cccclxi. (viii. Gen.), fig. 126 



{pessime). 



February 10, 1873. Tenerife, Canaries. 70 fathoms. 



July 28-31, 1873. St Vincent, Cape de Verdes. 7 to 25 fathoms. 



Habitat. — Bahia (Reeve) ; Madeira (Watson) ; and Canaries (d'Orbigny). 



Fossil. — Post-pliocene of Calabria (Seguenza). 



Under Natica mamilla, Linne, I have referred to some of the features which markedly distinguish 

 this species from that of Linne. I regret that I am not able to compare the opercula of the two 



