124 PTERODISCUS. 



peripherally, brown with some irregular yellowish streaks, 

 nearly lusterless. Whorls 31/2, the first perceptibly convex 

 at the beginning, soon becoming flattened, the first half of 

 the second whorl a little impressed above the suture, which 

 thus appears margined for a short distance. It is sculptured 

 with very fine oblique growth strite, with some coarser wrin- 

 kles on the last whorl. Last whorl is rather bluntly carin- 

 ated, the keel on the last half whorl bearing an irregular 

 flange or "wing" of adhering earth; base convex, obtusely 

 angular around the tubular umbilicus. Aperture oblique, 

 much wider than high, the lip thin and simple, the colu- 

 mellar margin dilated, bearing a very low, indistinct spiral 

 ridge in the middle. This ridge is in the substance of the 

 shell, and is hardly perceptibly thickened by callous deposit, 

 Alt. 3, diam. 8 mm. 



Kalaikoa, Oahu (D. D. Baldwin). Type No. 58,159, A. N. 

 S. P. Ewa (C. M. Cooke) ; Wahiawa (D. Thaanum). 



Endodonta (Pterodiscus} alata Pfr., PILSBRY, Manual of 

 Conch., ix, p. 36, pi. 4, fig. 44 (no 'specific description or 

 measurements). --Endodonta (Pterodiscus) luesleyi SYKES, 

 Proc. Mai. Soc. Lond., ii, p. 127, 1896, based upon preceding 

 reference. Pterodiscus ivesleyi SYKES, Fauna Hawaiiensis, 

 Moll., p. 292. PILSBRY & VANATTA, Proc. A. N. S. Phila. 

 1905, p. 573, pi. 39, f. 7, 8, 9. 



This shell agrees well with Pfeiffer's description of Helix 

 alata; but as the British Museum specimens under the name 

 alata and those in the Newcomb collection have the columella 

 strongly lamellate, it has been held by Mr. Sykes that 

 Pfeiffer overlooked the lamella. At all events, alata is cer- 

 tainly from Lanai, where it has been taken also by Mr. 

 Perkins. Named in honor of Dr. Wesley Newcomb. 



The type specimen is fully described above and illustrated 

 on pi. 23, fig. 9. It is evidently not quite adult. The very 

 low columellar ridge or incipient lamella was overlooked in 

 former accounts of the species. 



Specimens from Wahiawa, Oahu, collected by Mr. Thaanum, 

 pi. 23, figs. 1 to 5, are typical, and being fully adult they 

 show the characters better than the type. The shell is red- 



