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. 45 2, lesser 35 J, 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 DESK. 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. 



