142 GASTROPODA. [Aspidobranchia. 



KEY TO SPECIES. 



A. Shell elevated, conoidal. All spiral lirae crossed by strong 



radiate riblets, strongly beaded ' . . . . . . textilis. 



B. Shell depressed, turbinate or orbicular. 



a. Penultimate whorl with 4, the last with about 10 spiral cords plicatula. 

 aa. Penultimate whorl with 6, the last with about 16 spiral 



cords . . . . . . _ semireticulata. 



3. Monilea plicatula, Murdoch and Suter, 1906. Plate 33, fig. 12. 



Minolia plicatula, M. & S., T.N.Z.I., xxxviii, 1905 (1906), 299, pi. 26, f. 47-49. 



Shell small, orbicular, widely umbilicate, thin and fragile, whitish 

 with radiate purplish streaks, longitudinally plicate above, and 

 spirally ribbed. Sculpture : There are rather distant oblique radiate 

 plications extending on the body-whorl to the periphery only ; these, 

 as well as the interspaces, are very finely longitudinally striate. On 

 approaching the umbilicus equidistant straight broad and flat riblets 

 are formed, slightly beading the revolving cords. The penultimate 

 whorl has 2 spiral ridges close together, flatly beaded by the radiate 

 plications, and 2 some distance down toward the suture. On the 

 last whorl are 2 spiral cords, somewhat removed from the suture, 

 followed by a smooth interstice and 3 spiral ridges with grooves of 

 their own width between them ; 5 narrower cords follow from the 

 periphery to the umbilicus, the grooves between which are first narrow, 

 then getting broader ; there is a double beaded ridge margining the 

 umbilicus. Colour whitish, with irregular radiate zigzag bands of 

 purple. Spire low, with a blunt apex. Protoconch smooth, rather 

 large, depressed globular, yellowish, of 1 whorl. Whorls 3J, shouldered, 

 convex at the periphery ; base flatly convex. Suture subcanaliculate. 

 Aperture subcircular, very little excavated above, the margins ap- 

 proaching and nearly meeting, slightly nacreous within. Outer lip 

 sharp, convex. Inner lip forming a very thin layer over the penulti- 

 mate whorl. Columella regularly arched, slightly reflexed, produced 

 at the base on joining the carina of the umbilicus. The latter is wide, 

 carinate, perspective, with spiral ridges and longitudinal plications 

 on the last whorl. 



Diameter Ma]., 4-5 mm. ; min., 3-8 mm. : height, 3 mm. 



Type in the Dominion Museum, Wellington. 



Hab.OS Cuvier Island, in 37 fathoms, type (Captain Bollons) ; 

 off Great Barrier Island, in 110 fathoms. 



4. Monilea semireticulata, Suter, 1908. Plate 33, fig. 13. 



Minolia semireticulata, Suter, P. Mai. S., viii, 22, pi. 2, f. 1. 

 Shell small, depressed turbinate, umbilicate, thin and fragile, 

 spirally lirate. Sculpture consisting of numerous slightly elevated and 

 rounded spiral cinguli, 6 on the penultimate, about 16 on the body 

 whorl, those on the upper surface with a fine spiral thread in the in- 

 terstices, which are of about the same width as the riblets ; the cinguli 

 on the outer side of the base are finer and closer together ; on the 



