HELIX-OBBA. 213 



H. mamilla FER. Hist., t. 25, f. 1, 2. QUOY & GAIMARD, Voy. 

 de 1'Astrol., Zool., ii, p. 93, t. 7, f. 1-3 (animal). PFR. Monogr. i, 

 p. 318; Conchyl. Cab. t. 138, f. 3-5. REEVE, Conch. Icon. f. 471. 

 MARTENS, Ostas. Zool., Landschnecken, p. 291. Semicornu mam- 

 illa WALLACE P. Z. S. 1865, p. 410. 



The figure on pi. 53 represent a small form corresponding to Fer- 

 ussac's types. I have figured a larger, finer specimen on pi. 40, fig. 

 95. Von Martens gives measurements of still larger specimens : 

 greater diam. 45J, lesser 35*, alt. 35 mill. 



It is an odd thing, quite unlike any other Helix. 



H. QUOYI Deshayes. PI. 53, figs. 96, 97, 98. 



Shell convex-depressed, not carinated, umbilicated, solid, opaque, 

 rich chestnut colored with a yellow or white line at the periphery ; 

 above having coarse, radiating folds ; below the periphery covered 

 with close, fine wrinkles, descending obliquely in a direction at 

 right angles to the striae of growth. Last whorl but slightly de- 

 scending in front ; lip broadly reflexed. 



Compact, solid ; the spire low, convex, having rude, irregular, 

 and uneven radiating folds ; below the periphery the surface is far 

 smoother, covered with close, fine wrinkles ; the umbilicus having 

 only growth-striae within. Whorls 5, but slightly convex ; suture 

 superficial ; the last whorl a little descending in front. Aperture 

 oblique, semi-oval ; entire peristome. broadly reflexed, its face thick- 

 ened, convex, white ; margins approaching, joined across the parie- 

 tal wall by a cord of white callus. Umbilicus deep, somewhat 

 cylindrical, permitting one to see to the apex within it. 



Alt. 30, greater diam. 57, lesser 38 mill. 



Northern Celebes. 



H. undulata QUOY & GAIM., Voy. Astrol. Zool. ii, p. 91, t. 7, f. 

 1, 2 (preoc.). H. quoyi DESH. Anim. s. Vert, viii, p. 105 ; Fer. 

 Hist. t. 73b, f. 4. PFR. Monogr. iv, p. 286 ; Conchyl. Cab. p. 358, 

 t. 137, f. 1-3. MARTENS Ostas. Zool. p. 289. LOEBBECKE & Ko- 

 BELT, Jahrb. d. m. Ges. vii, 1880, p. 332, t. 8, f. 2. 3. Semicornu 

 quoyi WALLACE, P. Z. S. 1865, p. 410. Vallonia undulata GRAY, 

 Fig. Moll., t. 72, f. 3. 



Allied to H. mamilla, but the obliquely spiral wrinkles of the 

 body-whorl descend in the opposite direction ; the form is more de- 

 pressed, umbilicus wider, and the whorl does not descend deeply at 

 the aperture. 



