Placostylus.] GASTROPODA. 765 



It therefore seems very probable that only one egg is laid after copu- 

 lation. 



Type in my collection. 



Hob. -Big King, Three Kings Islands (Captain Bollons). 



Remarks. P. Bollonsi is distinguished from all the other species 

 of the genus known to me by the obtuse broadly rounded apex. In- 

 teresting features are the costate. very rarely punctate, protoconch, 

 and the loss of the spermatheca. 



This species may be considered as a splendid example of the 

 (-: 'j;inating of a new species by isolation. 



2. Placostylus Hongii, Lesson, 1830. Plate 48, fig. 14. 



Bui/inn* Xlowiii, Less., Voy. Coq., Zool., ii, 1830. 321, pi. 7, f. 4, 5 (1826). 

 Kister, Conch. Cab., 55, pi. 16, f. 14, 15: M.H. Viv., ii. 140; iii, 378: 

 iv, 447 : Conch. Icon., v, pi. 54, f. lot). B. Honyii, Less. : Lesson and 

 Martinet, " Les Polynesiens," iv, 1884, 227. P/<w//////x ^hnmjii, Less., 

 Ad. G.R.M., ii, 153. Bnlhimx fibratus, .Mart.. Dictf. X.Z., ii, 247; not 

 of Martyn. B. bovinus, Brug. : Petit, .1. de Conch., 1853, 404 : Crosse, 

 I.e., 1864, 124 (with var. Candida) : -M.H. Viv., vi, 82 ; viii, 118 : Hector, 

 Cat. Land Moll. N.Z., 20. J^m-oxl////!* bovinus, Brug., Crit. List, 13; 

 M.N.Z.M., 14; Hutton, T.N.Z.I., xvi, 190; Hedley and Suter, P.L.S. 

 N.S.W. (2), vii, 632 ; Suter, J. de Conch., xli, 236 ; Kohelt, Conchyl. Cab., 

 Placostylus, 36, pi. 9, f. 1. Bulimus auris-boviuu. Petit, J. de Conch., 

 1853, 403-5 ; Crosse, Revue. Zool., 1855, 82. Pht<-<>*tnhi Hltr>n</ii, Less. : 

 Pilsbry, Man. Conch. (2), xiii, 22, pi. 11, f. 5-8. 



Shell large, oblong-conic, imperforate or rimate, solid, yellowish- 

 brown, somewhat shining, peristome smooth or with a few tubercles ; 

 without parietal nodule. Sculpture : The protoconch is finely axially 

 wrinkle-striate, but this ornamentation is usually worn off, and the 

 surface appears to be punctate ; the succeeding whorls are smoothish, 

 with low rounded and oblique folds, stronger below the suture, crossed 

 by very faint distant spirals ; the axial folds are mostly very well deve- 

 loped on the last half of the body-whorl. Colour varying from yellow 

 with numerous narrow chestnut streaks to chestnut with blackish 

 streaks : paler or denuded on the earlier whorls, and with a whitish 

 subsutural border, denuded of epidermis ; aperture scarlet within. 

 fading to yellow in the throat, the peristome whitish at the margin. 

 Epidermis thin, brown, shining, more or less rubbed off. Spire 

 elongate, higher than the aperture ; outlines convex. Protoconch 

 obtuse, of 2 whorls, finely axially wrinkle-striate when intact, but 

 mostly much worn and polished. Whorls 6J to 7, moderately convex. 

 the last rather rapidly increasing, and the latter part of it some- 

 what swollen below and obliquely produced ; base rounded. Suture 

 not much impressed, uneven. Aperture vertical, oblong-oval, angled 

 above. Peristome continuous. The outer lip expanded, thickened 

 and angular on its face, thickened within, and typically bearing a 

 tubercle near the upper insertion, separated by a short interval from a 

 low or strong flange, which may be either smooth or denticulate, and 



