EEPORT ON THE GASTEROPODA. 401 



Itanella argus, Kiister, Conch. Cab. (ed. Kiister), p. 125, sp. 2, pi. xxxvii. figs. 5, 6, and Ranella 



vezillum, p. 126, sp. 3, pi. xxxviiia. figs. 1-3. 

 Bursa (Apollon) proditor, v. Frauenfeldt, "Novara" Moll., p. 4, pi. i. fig. 1. 

 Ranella argus, v. Martens, Siidafrik. Moll., Jahrb. deutsch. malak. Gesellsch., 1874, p. 134, sp. 113. 



„ {Apollon) argus, Kobelt, Jahrb. deutsch. malak. Gesellsch., 1876, p. 326, sp. 1, and Ranella 

 (Apollon) proditor, sp. 3, and Ranella vexillum, sp. 4. 



„ (Bursa) proditor, Velain, Moll. St Paul et Amsterdam, p. 100, pi. ii. fig. 5. 



„ argus, v. Martens, Crit. List New Zealand Moll., p. 23. 



„ vexillum, Hutton, Manual, p. 65. 



„ (Argobuccinum) argus, Tryon, Manual, vol. iii. p. 44, pi. xxiv. figs. 61-65. 



October 15, 1873. Tristan da Cunba. Shore. 



Station 135c. October 17, 1873. Lat. 37° 25' 30" S., long. 12° 28' 30" W. Nightin- 

 gale Islaud, Tristan da Cunba. 100 to 150 fathoms. 



Habitat. — New Zealand, Australia, Tasmania, St Paul and Amsterdam Islands, Cape of 

 Good Hope, South America. 



This form from Tristan da Cunha, which bears in the British Museum the name Apollon tris- 

 tensis, is somewhat longer and narrower than the type, with a more tumid and less scalar spire, but 

 this latter feature arises from the varices being more continuous, and of this peculiarity examples are 

 not wanting, especially in the form which Sowerby has described as Ranella vexillum. The opinion, 

 strongly expressed by Deshayes and others, of the specific distinctness of this form from the Ranella 

 argus, Gm., deserves much weight, and it is not difficult to pick out specimens very strongly marked 

 with the distinguishing features of difference which have been dwelt on by the authors I refer to ; but, 

 on careful survey of a large number of shells, I felt driven to the conclusion that they all belonged to 

 one species. Having formed this conviction, it was with great satisfaction that I found it was the 

 opinion already expressed (Jahrb., loc. citi) by so thoroughly competent a judge as v. Martens, and 

 that substantially on the same grounds. At the same time, at p. 268 of his Beitrage zur Meeresfauna 

 der Insel Mauritius, &c, Mollusken, referring to Dufo, p. 55, as attributing Ranella argus, Lam., to 

 Mahe, in the Indian Ocean, he says : " Es ist dies eine siidafrikanische Art welche nicht wohl so 

 weit in die Tropenzone hinein sich erstrecken diirfte ; vermuthlich falsche Bestimmung." Notice 

 too his identification of it as a New Zealand species. 



7. Ranella {Argobuccinum) leucostoma, Lamarck. 



Ranella leucostoma, Lamarck, Anim. s. vert., voL vii. p. 150, and (ed. Desh.) vol. ix. p. 542, sp. 2. 



„ „ Deshayes, Encycl. method., vers, vol. iii. p. 878, sp. 12. 



Triton leucostoma, Quoy and Gaimard, " Astrolabe," Zool., vol. ii. p. 546, pi. xl. figs. 3-5. 

 Ranella leucostoma, Kiener, Iconog., p. 29, sp. 21, pi. ix. fig. 1. 



Triton leucostoma, Gray, Fig. Moll. Animals, vol. ii. pi. lxxxv. fig. 1 (Ranella leucostoma), pi. cvi. fig. 2. 

 Ranella leucostoma, Eeeve, Conch. Icon., vol. ii. pi. i. fig. 2. 



„ „ Kiister, Conch. Cab. (ed. Kiister), p. 127, sp. 2, pi. xxxviia. fig. 4. 



Bursa leucostoma, Angas, Port Jackson Moll., Proc. Zool. Soc. Lond., 1867, p. 189, No. 18. 

 Ranella leucostoma, Hutton, Cat. New Zealand Shells, p. 13. 



„ „ v. Martens, Crit. List New Zealand Moll., p. 23. 



„ „ Hutton, Manual New Zealand Moll., pp. 64, 202. 



„ (Argobuccinum) leucostoma, Tryon, Manual, vol. iii. p. 42, pi. xxiii. figs. 53, 54. 

 (zool. CHALL. EXP. — PART XLII. — 1885.) Tt 51 



