BY H. LEIGHTON KESTEVEN. 467 



inar lirse and close-set transverse strise. Towards the end of the 



o 



embryonic structure there are faint indications of three extra 

 spiral lirse, which are suddenly developed on the adult structure. 

 The sculpture of the anterior whorl of this and all other species 

 studied (with one exception ■?) fades away as the nucleus is 

 approached. 



LOTORIUM RADIALE, Tate, Sp. 



(Plate xvii., fig. 2.) 

 Triton radialis, Tate, op. cit. p. 118, pi. v., f. 8. 



Apex of a little more than one and one-half whorls, polished; 

 nucleus mammillate, eccentric, placed rather to one side of the 

 centre, in some instances slightly overlapping the succeeding 

 whorl; the rest of the protoconch normal, gradually acquiring a 

 sculpture consisting of three spiral threads, the uppermost median, 

 and faint transverse growth-stri?e. There is also a very faint 

 indication of a fourth spiral thread half-way between the upper- 

 most of the three mentioned and the posterior suture. 



Harris (15, p. 187, pi. vi., f, 6) describes this apex as consisting of 

 two and one-half whorls, whilst his figures show the number I 

 have found. The term " lateral " applied by Tate and Harris to 

 the nucleus of this and other protoconchs of this series is some- 

 what misleading. The whole apex is truly spiral, but the nucleus 

 being somewhat mammillate and large relatively to the rest of the 

 protoconch is placed eccentrically. This apex is defined by a 

 complete change in the sculpture of the shell. 



LoTORiUM TUMULOSUM, Tate, sp. 



(Plate xvii., fig. 3.) 



Triton tumulosus, Tate, op. cit. p. 122, pi. v., f. 2. 



"Apex of two polished whorls; the anterior one is high, 

 bicarinated, and transversely striated; the posterior one, encircling 

 a shallow concavity, at first suddenly narrowed, then somewhat 

 depressedly dilated, and ending in a blunt appressed point." 



