70 HELIX-THERASIA. 



simple, the margins not converging ; columellar margin reflected. 

 Greatest diameter '25, least '2, height '15 inch. (Hutt.) 



Dunedin, New Zealand. 



Therasia Valeria HUTT., Tr. N. Z. Inst. xvi, p. 183, 202, t. 9, f. 

 N_ H. hypopolia HUTT., Ibid, xiv, p. 151, t. 3, f. B, not of Pfr. 



Differs from thaisa in the narrow umbilicus, from ophelia in being 

 ribbed. My figures were drawn by Mr. Suter from Prof. Mutton's 

 type. 



G. OPHELIA Pfr. (Manual II, p. 211.) 



B. Narrowly umbilicated species. 



G. TAMORA Hutton. PI. 22, figs. 49, 50, 51. 



Shell small, conical, umbilicated, with membranous plaits; color 

 horny-brown. Spire conical, rather acute ; periphery subangled . 

 suture impressed ; whorls 5-6, rather flattened, finely striated and 

 with irregular distant membranous ribs, easily rubbed off; umbilicus 

 narrow but open ; aperture transversely oval ; peristome thin, the 

 margins converging. (Hutt.') Alt. 2'5, diam. 4 mill. 



Auckland, New Zealand. 



Therasia tamora HUTTON, Tr. N. Z. Inst. xvi, p. 182, 202. 



Differs from celinde in the open umbilicus, and from decidua in 

 being more conical and smaller. My figure is from the type. 



G. THAISA Hutton. Vol. IX, PL 3, figs. 14, 15, 16. 



Shell rather solid, depressed, umbilicated, striated ; color pale 

 brown, usually irregularly banded and marked with reddish-brown. 

 Spire conoidal, obtuse; whorls 5-5, slowly increasing, rather flat- 

 tened, more or less obscurely angled, strongly but irregularly striated ; 

 suture impressed ; umbilicus rather narrow, about one-seventh of 

 the least diameter of the shell; aperture rather oblique, rotundly 

 lunate; peristome thin, the columellar margin rapidly ascending 

 and rather reflexed. Greatest diameter '4, least '35 height '28 inch. 



Animal elongated ; the foot long and narrow, reaching beyond 

 the shell, rounded behind, slightly truncated and with a mucus 

 gland situated under a caudal papilla. Mantle subcentral, included ; 

 body roughish ; peduncles long, cylindrical, approximated at their 

 bases; tentacles moderate. Top of the head yellowish-white, 

 peduncles, tentacles, and a line down each side of the head dark 

 gray ; a broad longitudinal band of white, with a dark gray line 



