470 NOTES ON PROSOBRANCHIATA, 



LoTORiuM TORTiROSTRis, Tate, sp. 

 (Plato xvii., fig. 8.) 

 Triton tortirostris, Tate, op. cit. p. 123, pi. v., f. 7. 



Apex normal, of three whorls, polished, nucleus very slightly 

 depressed, the anterior whorl ornamented by a median spiral 

 ridge, and a very slight thread midway between this and the 

 posterior suture, transversely obliquely striate, defined by the 

 acquisition of the adult sculpture. 



Compare with this the description of the protoconch of L. 

 parkinsonianum, Perry. 



LOTORIUM TEXTILE, Tate, sp. 

 (Plate xvii., fig. 9.) 

 Tritort textilis, Tate, op. cit. p. 120, pi. v., f. 12. 



" Apex acute of three rounded Urate whorls, ending in an acute 

 upward-curved point." 



The above is Tate's description; none of the specimens I have 

 examined possess perfect protoconchs. The sculpture on the 

 anterior whorl of the specimen figured consists of six revolving 

 threads and rather distant fine growth-strise. This apex is not 

 clearly defined; its termination seems to be indicated by a slight 

 transverse swelling (an aberrant varix ?), and the ending of the 

 polished surface. Judging from the material to hand it seems 

 probable that Tate counted from the first varix. 



The apex has rightly been considered a feature of systematic 

 importance by most recent writers. Unless, as is evident we 

 should do, we regard all the apices here discussed as varieties of 

 one generic type, the division of this group will present some 

 extraordinary anomalies. If the group is to be split up into 

 various genera it will be impossible to disregard the form of the 

 apices, now that we know so much about them ; and we shall 

 have such dissimilar species as L. costatum, Born, and L. cornutum, 

 Perry, in the same genus, and species so absolutely alike as L. 



