188 



of two turns, the posterior of which is smooth and slightly oblique, 

 whilst the anterior is spirally lineate. In regard to ornament 

 of the whorls, the compressed angulate tubercles are not rela- 

 tively as large as in the species mentioned, and the spiral lineations 

 are stronger. But the principal distinguishing features beyond 

 the protoconch are the prolonged anterior canal, the thin outer 

 border of the aperture, and the absence of pronounced lirae in 

 the interior; a thin columellar callosity is observable in many 

 individuals. 



Dimensions. — Length 38'.5 mm. ; breadth 23 mm. ; length of 

 aperture 15 mm. ; length of canal 10 mm. 



Form, and Loc. — Eocene : Muddy Creek, Yictoria. 



G. 9397. Examples of the neanic and ephebic stages of growth, 

 the shell of the latter being extremely thin. Purchased. 



Lotorium tumulosum, Tate (sp.), 



1888. Triton tumulosus, Tate, Trans. Roy. Soc. Soutli Aust. vol. x. p. 122, 



pi. V. fig. 2. 

 1893. Triton tumulosus, Tate and Dennant, id. vol. svii. pt. 1, p. 219. 



The protoconch is not very well preserved in any of the speci- 

 mens in the Museum collection ; the author of the species describes 

 it as follows: "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 depressly dilated, and ending in a blunt appressed 

 point." Z. tumulosum is allied to Z. ci/pkus, but the shape of 

 the whorls is different, the latter species being much more angu- 

 late, and the peripheral tubercles being so flattened as to resemble 

 serrations, whereas in Z. tumulosum the tubercles at the periphery 

 are nodose and cut up by small spiral sulci. Further, the spiral 

 ornament of the latter species is different, the threads being 

 markedly granose, whilst the anterior canal is shorter. 



Compared with the living Z. fusiformis, Kiener, of Australian 

 seas, the fossil has a longer canal, larger aperture, the denticles 

 on the outer margin are not so large and they are more numerous, 

 whilst the spiral ornament is more profuse. 



