78 Dr Grant on a New Zoophyte 



able plants. The season was not, however, sufficiently ad- 

 vanced, the mountain being still covered with snow, and, besides, 

 it would have required at least a day or two. We, therefore, 

 returned to Avignon in the evening." 



(To be continued.) 



Notice of a New Zoophyte (Cliona celata, Gr.) from the 

 Frith of Forth. By R. E. Grant, M.D. F.R.S.E. F.L.S. 

 M.W.S. &c. Communicated by the Author. 



W E frequently find on the shore the decayed shells of the 

 common oyster, (Ostrea edulis. Lam.) entirely perforated on 

 both sides with small round holes, about half a hne in diameter. 

 These holes do not pass in a straight line through the substance 

 of the shells, but open on both sides into chambers, which have 

 been somehow excavated in the interior of each valve : they have 

 probably been perforated by some marine worms, in order to 

 feed on the animal matter connecting the layers of the shell, and 

 to obtain a safe abode, as we generally observe a variety of these 

 animals come from the interior, when such shells are kept a few 

 days in a vessel of sear-water. When these perforated shells are 

 first brought up by the dredges from the oyster-beds of the Frith 

 of Forth, I have almost always found the holes on their surface, 

 and the excavated chambers between the layers, filled with a soft 

 yellow organised matter, which appears not to have been de- 

 scribed by naturalists, but whose singular properties entitle it to 

 a minute examination. This yellow fleshy substance occupies 

 the perforated shells of the living oyster, as well as the detached 

 valves of the dead animal ; but, in the living oyster, as the per- 

 forations are only seen on the outside, and never pass through 

 the innermost layer, there is always a thin layer of shell between 

 the yellow substance and the living animal. On the death of 

 the oyster, and separation of its valves, the inner layer soon be- 

 comes likewise perforated, and the yellow matter is then seen 

 projecting through the holes on both sides of the shell at the 

 same time. By removing successively the outer layers, we easily 

 discover that the internal excavations communicate freely with 

 each other, and with the apertures on the surface, and that all 



