Dr. Philii)pi on the Ocullna ramea of Ehrenberg. 93 



appears to be rare. The animal is entirely white, semi-trans- 

 parent. The mantle is split in its whole anterior half for the 

 exsertion of the foot, the margin is entire ; behind there is a 

 small aperture for the exit of the water and the excrements. 

 Where the mantle quits the margin of the shell there are on 

 each side eight or nine short cirri or rather warts. Between 

 the vertex and the aperture of the foot there is also one, and 

 between the vertex and the posterior aperture three warts. 

 The epidermis is highly remarkable ; it easily frees itself from 

 the shell which is quite enveloped by it, and hangs to the 

 mantle {a in fig. 4 d,) ; it appears therefore to retain constantly 

 its organization, while in most bivalves it very rapidly dies, 

 yet I would not with M. Scacchi call the shell interior. The 

 foot is nearly cylindrical and can be stretched out to a great 

 length,but it never produces jumping motions, but crawls with 

 its white under surface quite after the manner of the Gaste- 

 ropods, even up the smooth perpendicular side of a glass, 

 which by the bye I have also seen done by Lucina commutata* 

 Thrown into spirits the animal exhibits at the base of the foot 

 a cavity surrounded by a circular prominence, which I sus- 

 pected to be an organ for the secretion of a byssus, but not a 

 trace of byssus was to be seen either on the roots of the Zos- 

 tera or on the glass. When the mantle is cut open in the 

 centre an almost globular body makes its appearance, which 

 is divided posteriorly by a shallow groove, and on each side are 

 seen two large equal branchiae terminating free posteriorly. 

 On each side in front are two oval moderately large appen- 

 dices buccales. The two adductors are not evident when the 

 animal lies on its back, but are distinctly recognised when in 

 the reverse position ; the hinder one is roundish, nearer to 

 the margin, and somewhat larger than the front oval one. 

 The shell has been elsewhere sufficiently described, but I 

 would hardly call the hinge callous, and the ligament appears 

 to me to be quite internal. A second external one occupies 

 the whole margin of the hinge. The two magnified figures 

 sufficiently show the form and sculpture. 



4. Oculina ramea^ Ehrenberg; Car yophy Ilia ramea, Lamk. 

 Few persons have seen the animal of this common coral, nor 



