1 



Genus 2. STRUTHIOLARIA, Lamarck. 



Animal ; disc large, thick, carrying a small horny rudimentary 

 operculum behind, supported in the centre by a stout pedicle 

 ivhich passes into the shell, and serves to support the head; 

 head rather large, prolonged into a cylindrical trunk enclosing 

 the mouth, at the base of ivhich on either side are two long 

 pointed tentacles tvith eyes at the lower outer side ; no respi- 

 ratory sij)hon. 



Shell ; oblong-oval, spire exserted, rather obtuse at the apex ; 

 columella curved, truncated at the base, outer lip thickened, 

 slightly sinuated toioards the lower part. 



A limited genus of moUusks, inhabiting the shores of New Holland^ for 

 a description and figure of whose soft parts we are indebted to the 

 researches of ]\I. M. Quoy and Gaimard. Their chief peculiarity consists 

 in tbe disk being supported on a stout pedicle which passes into the shell, 

 in the truncated proboscidiform prolongation of the head, indicative of the 

 relation of tliis mollusk with Aporrliais, and in the absence of any respi- 

 ratory siphon, which is so conspicuous a feature in the Purjmrifera, and is 

 formed, as observed m treating of that family, by an elongated fold of the 

 mantle, protuding in an erect position through the basal notch of the shell, 

 for the purpose of supplying water to the breathing organs. 



Prom the circumstance of the outer lip of the shell of Struthiolaria 

 beino" unusually thickened and rolled back, whilst a corresponding 

 thickness is displayed in the superincumbent deposit of enamel on the 

 opposite side, described as the columellar lip, the genus was referred by 

 Lamarck to the immediate vicinity of the Tritons and Ranella, regarding, 

 this structure as an analogue of the varices by which those genera are 

 characterized ; Mr. Gray and M. Deshayes, however, observing the marked 

 resemblance which the shell of StrutUolana presents to that of Aporrhms 

 in the sinuated hp and truncature of the columella, removed the genus 

 under consideration, almost simultaneously, to the family Alata, and their 

 anticipations of its true character have been confirmed in a striking manner 

 bv the observations of Philippi and M. M. Quoy and Gaimard. 



Species. 



1. crenulata Lam. 3. papnlosa {Buc.) Mart. 5. straminea {Murex)G^m. 



2. microscopia. Gray. 4. scutulata (^2<c.)Mart. 



Figure. 

 Struthiolakia straminea. pi 8. Pig. 38. Shell, sho^nng the thickened 

 outer and columellai- Kps and truncature of the columella. 



