PLACOSTYLUS, NEW,, CALEDONIA. 53 



P. SENILIS (Gassies). PL 10, fig. 30. 



Shell much compressed, similar in general characters to P. gues- 

 tieri, but larger, enormously thick and ponderous, the face of the lip 

 built forward in a huge flange. 



Alt. Ill, diam. 58 mill, (specimen). 



Alt. 129, diam. 65 mill. (Gassies' type). 



Fossil ; Islet Koutoumo and Isle of Pines, very abundant. 



Bulimns senilis GASS., J. de C., 18C9, p. 71 ; Faune ii, p. 65, pi. 

 2, f. 15 ; J. de C., 1880, p. 327, pi. 10, f. 3 (sinistral form). PFR., 

 Monogr. viii, p. 19; Nomencl. Hel. Viv., p. 216. CROSSE, J. de 

 C., 1873, p. 52. Placostylus senilis KOBELT, Conchyl. Cab., p. 20, 

 pi. 4, f. 1 ; pi. 5, f. 1, 2 (var. minor). 



This extraordinary form scarcely differs specifically from P. gues- 

 tieri, and the " var. minor " (pi. 20, fig. 42) figured by Kobelt, meas- 

 uring 90 mill, in length, practically unites the two. Gassies has fig- 

 ured a sinistral example. 



The specimens occur in a layer of sand which overlies the coral 

 and is covered by humus. This layer is exposed by the uprooting of 

 trees, as well as where the sea has encroached upon the land. The 

 orange-red color of the interior often shows dimly, though the cuticle 

 is lost and the surface more or less chalky. 



Var. subsenilis (Gassies). PI. 9, fig. 28. 



Narrower and less compressed than P. senilis, the aperture more 

 contracted by larger teeth. Length 110, diam. 55 mill. 



Fossil, Isle of Pines (Lambert). 



Bulimus subsenilis GASS., J. de C., 1878, p. 331 ; Actes Soc. Linn. 

 Bordeaux 1880, p. 39, pi. 2, f. 1 ; Faune iii, p. 39, pi. 2, f. I. Placo- 

 stylus subsenilis KOBELT, t. c., p. 49, pi. 12, f. 1 (copied from Gas- 

 sies). 



P. BUCCALIS (Gassies). PI. 25, fig. 14. 



Shell imperforate, ovate, long, solid, shortly acuminate, longitudi- 

 nally streaked ; transversely striate, strongly malleated; dirty whitish- 

 roseate, the apex rose-tawny, obliquely streaked, shining, covered 

 with a chestnut-buff epidermis ornamented with irregular brown lon- 

 gitudinal stripes, and worn off on the apex and ventral face ; suture 

 appressed, white. Whorls 7, convex, the last two-thirds the total 

 length. Aperture large, long-ovate ; peristome fleshy, thick, sinu- 

 ated above, excavated, expanded and dentiform in the middle ; colu- 



