242 Lamarck's Ge7iera of Shells. 



they are long, are transverse, envelope the whole length of the axis, 

 and cover one another in succession, giving the shell a triangular 

 form, three chambers being rather more than sufficient to complete 

 a whorl. 



Type. Milliolites cor anguinum*. 



Shell subcordate, inflated, duplex ; aperture small, suborbicular. 

 Fossil, Grignon. PI. vi. Fig. 220. 4 Species f. 

 2. Melonites +. 



Shell subspherical, multilocular; spire central; whorls conti- 

 guous, enveloping, tuniciform. Chambers narrow, elongated, and 

 numerous ; septa imperforate. 



Type. Melonites sphcerica §. 



No further description. PI. vi. Fig. 221. 2 Species. 

 5th Family. 

 Radiolata ||. (3 genera.) 



Shell discoidal, spire central; chambers elongated, radiating from 

 the centre to the circumference. 



From the character of the shells of this family, it follows that 

 their spire can have but one turn, and is consequently false, or 

 imperfect. 



1. Rotalites %. 



Shell orbicular, spiral, convex or conoidal at the upper part ; 

 flattened, radiating, and tubercular, at the lower; multilocular. 

 Radii wavy. Aperture marginal, triangular, inclined towards the 

 base. 



The rotalites are very small shells, widest at the base, with the 

 whorls contiguous and distinct. The transverse septa which di- 



* Serpent's heart. 



t We omit the genus gyrogonites, altogether, on the authority of M.M. 

 Cuvier and Brogniart, quoted below. The truth of Leman's observation, has 

 since been confirmed by Mr. Sowerby. The passage alluded to will be found 

 at page 61, of the Description Geologique des Environs de Paris. Speaking of 

 the fossil shells of the third fresh-water formation, Messrs. B. and C. add, 

 " There are also found in it those small, round, channelled bodies, which M. 

 de Lamarck has named gyrogonites, and which, according to M. Leman's 

 'observations, appear to be the seed of a species of chara." 



t From melo, a melon. § SpMricaU \\ From radius, a ray. 



•R From rota, a wheel. 



