SYSTEMATIC "37 



Genus Notoficula Thiele, 1917 



n.nom. for Ficulina Thiele, 19 12, non Gray, 1867 



Type : Ficulina bouveti Thiele 



Thiele (1912, p. 270, pi. 19, fig. 13) based this genus upon a small ' Ficus '-shaped shell from Bouvet 



Island, which he first placed subgenerically under Cominella and later (1929, p. 315) as a section of 



Chlanidota. 



Living examples, possibly not fully adult, of what appears to be an allied species are described below. 

 If my reference of these shells to Notoficula is correct, then that genus is indicated as allied to 

 Pareuthria and quite close to Tromina. These shells have a tricuspid central tooth and bicuspid laterals, 

 but the laterals are distinct from those of Pareuthria in that the two cusps are set much closer together 

 and the inner one is the more robust. Also the inner cusp is strongly incurved with a deeply concave 

 inner margin. The protoconch is dome-shaped and smooth, and the operculum ovate to D-shaped, 

 paucispiral, with the nucleus near to the lower inner margin, Fig. N, 125. 



Notoficula problematica n.sp., PI. VI, fig. 18 



Shell small, ovate, white, few whorled, surface regularly incised with spiral linear grooves. Whorls 3I, 

 including a relatively large, smooth, dome-shaped protoconch of if whorls. Spire less than half 

 height of aperture. Sculpture of post-nuclear whorls in the form of regularly spaced linear grooves, 

 which cut the surface into low, flat-topped spiral cords, nine on the penultimate and about thirty on the 

 body-whorl. The whole surface is crossed by dense axial threads, more conspicuous in the grooves. 

 Aperture ovate-pyriform, outer lip thin with a broad open anterior canal, neither produced nor 

 sinused, but partially constricted by a callused fold at the base of the pillar. Parietal wall deeply concave 

 medially, but not excavated, covered with a thin callus. Operculum much smaller than the aperture, 

 horny, ovate to D-shaped, paucispiral, the nucleus near to the lower inner margin. 



Height 5-25 mm. ; diameter 3-6 mm. (holotype). 



Height 6-9 mm. ; diameter 5-0 mm. (St. WS 766, a worn shell, probably adult). 



Type locality. St. WS 766. Between Falkland Is. and Argentina, 45 13' S, 59 56' 30" W, 

 18 Oct. 1931, 545 m. 



Dentition. Fig. K, 61, p. 193. Operculum. Fig. N, 125, p. 196. 



The material upon which this species is based may not be fully adult, but it is certainly distinct from 

 the larger bouveti, which is of more pyriform outline and has less conspicuous spiral sculpture. 



Genus Falsimohnia n.g. 

 Type : Buccinum albozonatum Watson 

 This genus has a dentition of similar style to that of the Boreal genus Mohnia Friele, 1878, but on 

 shell characters the relationship is much more in accord with Pareuthria or Glypteuthna. Both Mohnia 

 and Falsimohnia have the central tooth with a single cusp and bicuspid laterals. The reduction of the 

 cusps of the central tooth to a single member also occurs in the Mediterranean Chauvetia (=Lachesis 

 Risso), and this fact no doubt influenced Martens & Thiele in their placing oi Laches, s austrahs (1903, 



P- 62). f , 



I would consider Falsimohnia as a derivative of Pareuthria in which the normal three cusps ot the 

 central tooth have been reduced to a single member. There is a parallel case in the Naticoid genus 

 Tanea, which has a central tooth with only one cusp, whereas most other genera of the family are 

 tricuspid. Also the operculum of Falsimohnia has a blunt terminal nucleus as in Pareuthria, whereas 

 in Mohnia it is ovate and paucispiral. 



