55 



Species. 



1. australis, Lam. 4. depressa, Lam. 7. plicata, Forsk. 



2. cristate, id. 5. lineata, Recluz. 8. regularis, P/til. 



3. deltoidea, Dunk. 6. penicillata, Carp. 9. reniformis, Za;w. 



Figwe. 



Plicatula Philippinarum. PL 27. Pig. 161. Shell, with the upper 

 valve dropped to show the strongly-toothed hinge, and the absence of 

 umbonal area. 



Genus 3. HINNITES, Befrance. 



Animal ; supposed to be similar to that of Spondylus. 



Shell ; affixed, inequivalve, thick, ponderous, slightly auriculated ; 

 hinge and umbonal area in both valves broad and toothless, 

 with a central, rather deep, oblong -triangular pit containing the 

 ligament. 



We have seen that Plicatula has the teeth of the Spondylus, but no 

 umbonal area. Rhinites has the umbonal area of that genus, but no teeth ; 

 it moreover resembles Spondylus in the size and massiveness of its growth. 

 The genus was founded originally from two fossil species. The two recent 

 species referred to it are shells of great rarity in the collection of the 

 British Museum, — one described by Dr. Gray, in the ' Annals of Philo- 

 sophy/ the other by Mr. Sowerby, in the ' Zoological Journal.' Both are 

 figured in vol. viii. of the ' Conchologia/ An attaching species of Pecten 

 (Ostrea pusio, Linn.) has been referred to this genus, but it has little or 

 no participation in its characters. 



Species. 



1. corallinus, Sow. 2. giganteus, Gray. 



Genus 4. PECTEN, Bruguiere. 



Animal ; shaped as the shell ; mantle freely open, with pendent 

 margins, bearing, usually two, fringes of tentacular filaments, 

 the one series at their fixed, the other at their free border. 



