FULTON : MOLLUSCAN NOTES. 237 



crenulated suture ; falcifera is almost smooth, whereas, under the 

 lens, falciformis is seen to be very distinctly obliquely striated. The 

 internal plaits are similar in both forms. This comparison has been 

 made with original specimens of both species. 



No. 5. — The Identity of Ptekocyclos pkestoni, Bav. & Dtz., with. 

 Pterocyclos cochinchinensis, Pfr. 



Comparison of original examples of P. prestoni, received from 

 Colonel Messager, with the type of P. cochinchinensis demonstrates 

 that these two forms are identical. The colour of both is light 

 yellowish brown ; darker specimens with some irregular waved 

 markings above and a peripheral narrow band of darker brown were 

 named P. prestoni, var. depicta, Bav. & Dtz.; the larger specimens of 

 tliis variety cannot, in my opinion, be distinguished from Rhiostoma 

 morleti, Dtz. & Fisch. 



Judging by shell characters and the manner in which various 

 authorities have placed the same forms under different generic names, 

 the position of the sutural tube, upon which character the genera 

 Pterocyclos, Rhiostoma, and Opisthoporus are mainly founded, appears 

 to be of little significance. 



Synonymy of Pterocyclos cochinchinensis, Pfr. 

 1856. Opisthoporus cochinchinensis, Pfr., Proc. Zool. Soc, p. 337. 

 1865. Pterocijclos cochinchinensis, Pfr., Pneumonop. Viv., Supp., ii, 



p. 37. 

 1891. P. planorhulus, Morlet [non Lamk.), Journ. de Conch., 



vol. xxxix, p. 247. 

 1905. Rhiostoma morleti, Dtz. & Fiscli., Journ. de Conch., vol. liii, 



p. 429, pi. X, tigs. 1-4. 

 1908. Pterocyclos prestoni, Bav. & Dtz., Journ. de Conch., vol. Ivi, 



p. 248. 

 1908. P. prestoni, var. depicta, Bav. «& Dtz., Journ. de Conch., vol. Ivi, 



p. 249. 



Hah. — Cocliinchina (Pfr.); Tonkin (Morlet, Mansuy, and Messager); 

 Laos (Massie). 



No. 6. — On Dr. Anton Wagner's Monograph of IIelicinid.e in the 

 Conchylien-Cabinet, 1911. 



Whilst looking tlirougli the above work I was surprised to find 

 that many species have been omitted, and thought a list of such, 

 with the correction of some errors, might prove useful to otliers 

 when consulting that monograph. Probably some of the omitted 

 species, which number more than 100, are the same as some of the 

 numerous new species created b\- Dr. Wagner. 



In proposing a number of new genera and sub-genera for various 

 sections of the Helicinidae, Dr. Wagner has ignored many of 

 those of previous authorities, as may be seen by consulting the 

 Manuel de Conchylioloyie, 1887, of Dr. Paul Fischer. The sectional 

 mimes Oxyrhomhus and Pyrgndomus of Crosse & Fischer (Miss. Sci. 

 Mexi(jiie, Moll., ii, p. 399, 1893) liave also been omitted. 



VOL. XI. — march, 1915. 17 



