366 



AcMjE'a' crugis, Tenison- Woods. 

 PL xx., No. 7. 



Dental formula ; ' ' ^ ' ' . Radula long, composed of a 

 double row of oblong blocks in pairs, on each of which rests 

 a central tooth, having a large curved cusp at its apex, and 

 a small one at the base, both long and sharp. Fig la shows 

 the blocks of cartilage; fig. 76 the teeth in profile. 



Acm^ea septiformis, Quoy and Gaimard. 

 PI. xx., No. 9. 

 Dental formula 00(1 7 9 1) - - - m Radula practically identical 

 with that of A . cruris, the cartilage blocks are shorter and 

 denser, and the upper cusp is slightly larger. 



Acm^ea marmorata, Tenison-Woods. 

 PL xx., No. 8. 

 Dental formula 00 - (1 9 ° o 1) - - m Radula very similar to that of 

 A. cruris, but the upper and lower cusps are more nearly 

 equal in size. 



ACM,EA SUBUNDULATA, AngaS. 



PL xx., No. 10, x 300. 



Dental formula °. ' (1 '° 5 1) ' ' . Radula very similar to that of 

 A. cruris, the teeth and cartilage blocks are smaller, propor- 

 tionally to the size of the respective shells. 



'Z BULLOIDEA. ! 



' ■■■■ Bulla australis, Gray. 



: -. PL xx., No. 12. 

 •'■ Dental formula 1.2.1.2.1. Radula shows a peculiar claw- 

 like form of the central and lateral teeth. The single central 

 occupies more than one-third of> the row, having about eleven 

 cusps on a long plate4ike base in the form of a rake 4 , any of 

 them may be double, generally the central cusp* is small, the 

 adjoining two large, and the rest of gradually decreasing size. 

 The laterals have each about seven cusps of varying size along 

 the top of an irregular indistinct subtrigonal plate. The mar- 

 ginal is a simple non-cuspidate plate. 



SIPHONARIOIDEA. '. J 

 Siphonaria diemenensis, Quoy and Gaimard. 

 PL xx., No. 5, x 600. 



Dental formula 21 " 18 1 g 5 18 " 21 . Radula relatively very broad, 

 about 79 teeth in a row, about 14,615 altogether. Central 

 tooth with a single sharp cusp on a long narrow bifurcated 



