466 NOTES ON PROSOBRANCHIATA, 



pressed too far, for Tate (35) has shown that man}'- of the species 

 now inhabiting the tidal zone also occur in these beds. The 

 tabulation of these relationships would be productive of interest- 

 ing results. 



The protoconchs of Lotoriurti p^'otensutn and ahhotti are similar 

 to those of the Fusion, the elongate, fusiforme shape of the latter 

 also recalling that family. It is from this group that I would 

 suggest the genus Lotoriurti is descended. 



A prominent character of all the apices examined is their spiral 

 sculpture. This, it is interesting to find, exists in two recent 

 species {L. nodocostatum and L. philomelce)* and is sometimes 

 found on the corneous originals of other species. On a superficial, 

 or first examination, the student is apparently presented with two 

 or three different types of apex. A closer study discloses the 

 fact that they are morphologically only varieties of one form. 

 The difference lies in the size of the nucleus, and the extent of 

 its depression or elevation. A study of the apices in profile gives 

 the first impression, whilst this view studied in conjunction with 

 the view from above, proves the correctness of my conclusion. 

 The following are the apices studied; like those of the recent 

 species they have been arranged in a graduation; that from the 

 very eccentric protoconch of L. looodsi to the normal ones of 

 oligostirum and tortirostris. These two being normal they have 

 not been figured from above : — 



'&' 



LoTORiUM wooDsi, Tate, sp. 



(Plate xvii., fig. 1.) 



Triton tvoodsi, Tate, Proc. Roy. Soc. S. Aust., x., 1886-7 (1888), 

 p. 119, pl.v, f.4. 



Apex of two whorls; the first half whorl perpendicular to the 

 plane of coiling of the shell; second half normal, but slightly 

 overlapping the second whorl; first whorl smooth, dull; second 

 whorl normal, polished, faintly biangled, sculptured by two revolv- 



* Vide also P. [ = L.]frateradum. 



