138 EOCENE MOLLUSCA. 
the check-tape of a trunk, to prevent its being opened too widely. This might be so if it 
were attached to the shell. I should be disposed to attribute to it quite a contrary 
action, and to believe that its use may be to strengthen the hinge and to prevent its 
being squeezed too closely and broken, as is frequently the case with certain species of 
Anatina and Thracia.” ‘The ossicle in Verticordia is convex on one side and concave on 
the other, and the concave side fits over a tubular projection under the dorsal margin of 
the left valve, in which the cartilaginous connector is inserted. In the right valve the 
connector is naked or unprotected, extending backwards within the margin a little beyond 
the ossicle joining the portion of the left valve; this ossicle reduces the large space 
between the two umbones, and is a partial ossification of the mternal connector, appearing 
to support the cartilage by a closer and more direct action in counteracting the contraction 
of the adductors instead of a long lateral extension across the deep umbonal region. 
My Crag species is thick, strong, and convex, and among about a hundred specimens 
(good and bad) that I have collected from the Coralline Crag I have never seen one 
fractured in the umbonal region; its large adductors and projecting riblets must enable 
the animal to firmly close itself within the shell. The absence of the ossicle in 
Pandora may be from the form of the valves, the upper one being somewhat convex 
internally, by which the connector would have a nearer and more direct or vertical action. 
In my Monograph of the ‘Crag Moll.” vol. ii, p. 150, the Crag species was 
thought to be the same as a fossil from Calabria, figured by M. Philippi under the generic 
name of ZZippagus, which I adopted. Dr. Lea, who proposed the name of Hippagus, has 
lately sent to Mr. Jeffreys a specimen of the American fossil so called. This appears to 
belong to the family A/yé/ide, and in no way related to Verticordia. I have therefore 
resumed the generic-name proposed for this Crag shell when first figured in ‘ Min. Conch.,’ 
t. 639, in 1844, viz. Verticordia, and I purpose here to introduce some Eocene shells 
init. This name Verticordia, I should add, was employed by Dr. J. E. Gray in his ‘ Brit. 
Mus. Catalogue’ for 1840, and he tells me (in letter) that he merely adopted it as my 
manuscript name; both he and myself then imagining the genus to belong to the 
Lucinide. 
M. Fischer, in the ‘Journ. de Conch.,’ vol. x, p. 378, has enumerated five recent 
species and four fossil, but this number will have to be considerably reduced. One fossil 
that may be referred to this genus has been long known, and was described as Chama 
argentea in 1797, according to Pecchioli, and in 1852 this shell was proposed as the type 
of a genus by Meneghini, under the name of Pecchzolia. 
The four Eocene species I propose here to introduce are very rare and have the two 
valyes united, or at least are the casts of those shells when so existing, and the 
interiors are not visible, though I have no doubt of their belonging to this genus, and 
possessing the same kind of hinge as my little Crag shell. M. Deshayes has figured and 
described one species from the Paris Basin. In the sandy formation of the Coralline Crag 
the valves, as might be supposed, are separated and displaced, with the ossicle, of course, 
