PLEUEOTOIIA. 89 



G. 4232. Two specimens ; from Muddy Creek. 



Presented hy Johi Dennant, Esq. 



G. 5502. A very elongate example, from Muddy Creek. 



Furchased. 



Pleurotoma septemlirata, sp. nov. 



[Plate II. Figs. lOa-i.] 



Shell large, fusiform, tumid ; protoconch small, smooth, devoid 

 of ornament, terminating abruptly at its junction with the shell 

 in the brephic stage ; whorls eleven in number, suture canaliculate 

 and bimarginate, rugosely spirally Urate ; there are seven principal 

 spirally striated lirae on the penultimate whorl in the adult, but 

 at younger stages of growth they are fewer in number, decreasing 

 gradually to four ; the body-whorl is irregularly Urate throughout. 

 Between the large compound liration on the margin of the suture 

 anteriorly, and the elevated ridge denoting the position of the 

 sinus, is a broad, deep sulcation, which, like the sulci between 

 the lirce, is finely spirally striated and interrupted by lines of 

 growth. Aperture large, broad, ovate, contracted anteriorly ; 

 outer margin thin, sulcate within, crenulated or serrated, arcuate ; 

 sinus broad, deep, situated distantly from the suture ; columellar 

 margin smooth, curved, slightly callous in senile individuals ; 

 canal very short and broad. 



Typically this species has some analogy with P. murndaliana, 

 but is larger, more tumid, has a shorter canal, and is not sub- 

 granose, whilst the deep, broad sulcation in front of the suture 

 is characteristic. Its great range of variation is remarkable, and 

 might at first sight lead to the establishment of several new 

 species. The type specimens, as above indicated, are strongly 

 Urate, but with sufficient material these may be traced almost 

 to the vanishing point, some individuals, indeed, being only very 

 faintly striated, and to all intents and purposes smooth. Pari 

 passu the shell is shorter and more tumid, presenting the aspect 

 of Pusionella, though it could not be classified with that genus, 

 on account of its deep sinus, amongst other things. 



Dimensions. — Length 60 mm.; breadth 22 mm.; length of aperture 

 25"5 mm. 



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



