342 



about .seven narrow flat thi"eads ; Ijody-whorl convex to the 

 rounded or subangulated periphery; Urate and crossed by slightly 

 sigmoidal incremental stride ; base flattened or subconvex ; aper- 

 ture oval : outer lip thin, medially ecurved ; columella thick, 

 arched, flattened, and margined at the exterior, callously united 

 to the outer lip. 



Dimensions. — Length, 4 : breadth, '1 (vix.). 



Loccility. — Eocene : " Turritella-bank.s," Blanche Point, Al- 

 dinga Cliffs (common I). 



This diminutive species of the genus is otherwise distinguished 

 by its st\»liform apex. 



FAMILY VERMETID.E. 

 Genus Thylacodes. 



Shell adherent, irregularly twisted, without laminje or keels 

 internal, but frequently concamerated. 



SYNOPSIS OF SPECIES. 



Posteriorly compactly coiled, afterwards lengthened. 



Whorls embracing forming a broad cone. 1. octinotus. 



AVhorls contiguous forming a cylinder. 



Surface lirate and finely costate. '1. crotericiilus. 

 Surface roundly costate. 3. cono1ieli:>\ 



Posteriorly irregularly and loosely coiled. 



Uncoiled portion much extended, densely squamosely ribbed. 



4. asjyer 



Uncoiled portion short : distantly ribbed. 5. rudi><. 



Shell vermiculate, slender, finely sculptured. 6. Adelaifhusis. 



1. Thylacodes aetinotus, -^pec. nov. PI. ix., fig. i. 



Solitary or rarely two together ; whorls embracing and 

 reciprocally adherent except the last turn, wliich is extended into 

 a very short erect tube. The aggregate mass is broadly conical ; 

 ornamented with thin lamellose radial ridge ; the free tubular 

 portion circular in section. 



Dimensions. — Diameters, 5 to 6 : height (ex. free tulje), 2-5. 



LocaJity. — Eocene : Adelaide-bore !. 



2. Thylacodes craterieulus, ^pcc. nor. Pi. ix., fig. H. 

 Solitary or twu together, early whorls irregularly coiled, 

 anterior whorls compacted, irregularly conoid or shortly cylin- 

 droid, finally obliquely-extended into a long much-narrowed tube. 

 Whorls ornamented with five or six spiral ridges crossed by 

 straight threads producing square or oblong fenestrations : basal 

 part of tul^e similarly ornamented gradually becoming obsolete 

 towards the extremity. 



