624 GASTROPODA. (Pidrnoitala 



cutting-point small ; the outer laterals with the refiexed portion more 

 oblique and its inner margin straight, the cutting-point moderate. 

 Marginals aculeate, with a long curved point. Jaw as in P. Helmsi. 



Type in the Canterbury Museum, Christchurch. 



// a fr. Stewart Island (T. Kirk) : Half-moon Bay, Stewart Island 

 (A. Hamilton). 



Subsp. costata, Suter, 1899. 



Phacussa fulminata costata, Suter, P. Mai. S., iii, 288, pi. 15, f. 9. 



This subspecies differs from the species in being always perforate, 

 somewhat larger in size, in being costate, and in having mostly a 

 different colour-pattern. The sculpture consists of subequidistant 

 low riblets, 4 to 5 per millimetre, the interstices with minute lines of 

 growth, which are decussated by spiral strise. Colour horny, with 

 broad oblique streaks, rarely zigzag bands of reddish-brown. Proto- 

 conch microscopically radiately striate. Suture not or but faintly 

 margined. Umbilicus narrow, deep, partly covered by the refiexed 

 inner lip. 



Diameter Maj., 12 mm. ; min., 11 mm. : height. 7 mm. 



Animal with a distinct caudal pore. 



Dentition (Suter, P. Mai. S., iii, 289). Jaw the same as in the other 

 species of the genus. Radula has the formula 25 + 15 + 1 + 15 + 25, 

 having 4 more teeth in each transverse row than the species, but 

 otherwise they are very much of the same character. The central 

 tooth is tricuspid, with the side cusps minute ; the laterals lack the 

 entocone, the mesocone being large ; these are followed by 4 transi- 

 tional teeth, and there are 21 marginals with an oblique mesocone 

 only. 



The reproductive organs (Plate 1, fig. 8) are very simple. The 

 male organ is broadest at its distal end ; at the outer end the re- 

 tractor muscle is inserted, and opposite to it the vas deferens enters. 

 The free oviduct is long and cylindrical, and on the side towards the 

 male organ the oblong receptaculum seminis, with a short distal 

 cjficum, takes its origin a little above the vestibule. 



Type in my collection. 



Hab. Resolution Island, type (R. Henry) ; The Nuggets, Port 

 Molyneux (A. Hamilton). 



2. Phacussa Helmsi, Hutton, 1883. Plate 25, figs. 3. 3a, 36. 



Zonites (?) Helmsi, Hutt,, T.N.Z.I., xv, 1882 (1883), 137. Phacvssa Helmsi, 

 Hutton, T.N.Z.I., xvi, 205; Hcclley ami Sutor, P.L.S. N.S.W. (2), vii. 

 635 ; Suter, J. de Conch., xli, 244. P. Helmsi, var. maculata* Hutt., 

 T.N.Z.I., xvi, 205; Hedley and Suter, I.e., (535; Sutt-r, t.c., 244. 



Shell depressed, umbilicated, finely ribbed, rather shining. Sculp- 

 ture, consisting of thin, rather distant, retractive, and sinuous radial 

 riblets, 5 to 6 per millimetre, the interstices with a few fine growth- 



