42 SYSTEMATIC ARRANGEMENT 



Some authors have placed this genus with Auricula ; but if the 

 above description of the position of the eyes is correct, it differs 

 from that family in that important character. 



Fam. XIV. TRITONIAD^l. 



Head truncated. Tentacles moderate. Mantle enclosed. Siphon 

 of mantle straight. Operculum distinct, annular, ovate or triangular ; 

 nucleus subapical, within the apex. Shell variced. Pillar veined 

 or grooved. Canal straight. Mouth ovate. 



M. d'Orbigny (Cuba, 160, 167, 168), not knowing the character 

 furnished by the teeth, observes that Triton is only separated from 

 Mureoc by conchological, and not by zoological characters ; in the 

 same manner he considers Fasciolaria and Pyrula as arbitrarily 

 rather than as naturally separated from Fusus ; but all the three 

 genera have most distinct zoological characters. 



* Operculum as large as aperture of shell, ovate ; varices rounded. 



1. APOLLON. 



Shell ovate, compressed ; varices two on each whorl, rounded, 

 forming a border to the shell. 



1. A. vexillum, t. 265. f. 1. 



2. A. foliatum, t. 84 a. f. 1. 



3. A. bufonium, t. 4. f. 2. 



4. A. graniferum, t. 4. f. 4. 



5. A. leucostomum, t. 85. f. 1, t. 116. f. 2. 



6. A. reticulare, t. 86. f. 1. 



7. A. cselatum. 



8. A. Rana, Adams, Gen. Moll. t. 11. f. 3. 



The teetli of Apollon graniferum are peculiar, 3 • 1 • 3 ; the central 

 one is narrow, with two diverging branches, having a central elon- 

 gated denticle, and a small lateral denticle in the middle of each 

 side of each lateral branch ; the inner 1 lateral compressed, with 

 three or four denticles on its front edge ; the outer lateral sub- 

 ulate, hooked (the teeth were not observed in position). The oper- 

 culum is ovate, rounded at each end, with a marginal apical nucleus. 



The Apollons live under stones below usual low water mark. 



2. Triton. 



Shell ovate ; spire conic, with three varices on each two whorls, 

 forming three interrupted longitudinal ribs on the shell. 



1. T. nodiferum, t. 3. f. 3 S, t. 85. f. 5, t. 3. f. 4 ? 



2. T. olearium, t. 3. f. 2, t. 263. f. 3. 



3. T. cutaceum, t. 3. f. 1 <? . 



