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DIVISION XIII. MEGASTOMATA. 



GENERA. 



A. In the form of a shield or cap. 



i. Gapulus. Montf. 



Conical, the summit 

 curving spirally. PI. 5, 

 fig. 13. 



Marine. 



Mediterranean. Bar 

 badoes. 

 V. Animal, p. 71. 



2. Hipponyx. ( 1 ) De 



France. 



Conical, summit in- Support adherent and 

 clined backwards. PL 6, bearing (as well as the 

 fig. 1. shell) a muscular impres- 



sion in the shape of a 

 horse-shoe. 



3. Ckepiduxa. Lam. 



Oval or oblong, the Half closed by a ho- 

 summit obtuse, inclined rizontal plate, 

 towards the edge. PL 5, 

 fig. 12. 



4. Calyptrjea. (2) Lam. 



Conical, the summit ver- 

 tical and pointed. 



Marine. 



Marine. 



On the rocks of the 

 Caribbean Sea. Mediter- 

 ranean. 



V. Animal, p. 72. 



Marine. 



Atlantic, Indian Seas. 



a The plate (adhering to the bottom of the cone) folded, and descending 

 vertically. PI. 5, fig. 8. 



b Infundibulum, Montf. The plate simple, almost horizontal, adhering to 

 the sides of tbe cone, which has a spiral line on the exterior. PL 5, fig. 20. 



5. Umbrella. Lam. 



Orbicular, slightly con- A callous, colored disk , Marine. 

 vex above, a small apex within. Mediterranean, In- 



near the summit. PL 5, dian Seas, 



fig. 15. 



(1) Several valves of different sizes having been found at Grignon, in the marl- 

 pits of Hauteville, Montmirail, etc. they were considered by some naturalists as 

 the type of the genus Acardo. M. Defrance having remarked a similar support 

 adhering to a recent shell (Patella mitrata, Gm.), foresaw that some other Patellae 

 were to be separated from that Genus to form the present. His conjectures were 

 afterwards realised by finding one of the fossil species on its support. 



(2) Foss. Grignon. 



(3) Foss. in the London Cloy ; Crag Mart ; Woolwich Loam ; Green Sand, 



