of the Chalk. 185 



described by Prof. Reid, were well-preserved, I immersed its face 

 in very finely prepared plaster of paris. On removing it after 

 the plaster had hardened, I found, under the microscope, an 

 appearance identical, as to the perforations, with that presented 

 by the casts of the Ventriculidse. 



The reader who may search for these remains of the moveable 

 processes on the Ventriculidse, and, as many will, may not find 

 them, and who may therefore too nastily doubt the accuracy of 

 my observations, will do well to refer to p. 332-3 of Johnston's 

 1 Zoophytes/ where he will find that, in even recent specimens, 

 " they are not present in every specimen of any of these species, 

 and indeed are very rarely to be seen on some of them, and when 

 present it is only upon some of the cells." If this is the case in 

 recent specimens how much more is it to be expected in fossil 

 specimens that the traces of the former existence of these pro- 

 cesses will be sometimes few, sometimes altogether absent ! The 

 universal friableness of the chalk and the general solidification 

 of the flint often almost or totally obscure them. Doubtless, 

 moreover, the originals of many of the specimens which remain 

 both in chalk and flint were dead when enveloped, — for the views 

 already stated require only that the soft parts should have been 

 yet undecomposed, not that the animal should have been alive. 



I am enabled, by some specimens in an extraordinary state of 

 preservation with which frequent personal excursions into the 

 field have rewarded my careful search, to add some description of 

 these processes as existing in the living Ventriculidse and derived 

 from other observation than that of mere casts only. When the 

 places of all are preserved, which is very rarely the case, they are 

 disposed not without some regularity : it would appear that one was 

 appropriated to each polyp, whose cell's mouth it doubtless swept 

 in the living state as the mouths of the polyp-cells of the Cellu- 

 laricB described by Prof. Reid are swept by the processes existing 

 in those species. As in those cases, the process was affixed to a 

 slight projection of the polypidom on the outer edge of each 

 polyp-cell. As in those cases also the processes tapered off gra- 

 dually to a point in the Ventriculidse, though the base of the 

 process was rather proportionally broader in the latter than in 

 the former. 



Any special peculiarities in these processes exhibited by any 

 species will be noticed in the descriptions hereafter to be given 

 of each separate species. 



The discovery of these moveable processes was certainly an im- 

 portant and very interesting point in the anatomy, as it was an 



purtenant to these processes, though Dr. Johnston does not describe the spe- 

 cies as exhibiting them. 



