PROCEEDINGS OF SOCIETIES. 173 



bodies!, enclosed in firm envelopes, which he has more rarely met 

 with, but which seem to break tiieir way out of the superficial cells, 

 may be ova. But on this part of the inquiry, nothing save observa- 

 tion of tiie animals in their living state can give satisfactory results. 



The regular type of structure just described is subject to numerous 

 variations ,\xito a minute description of wliich the author next enters; 

 the general results being, that neither the shape nor dimensions of 

 the entire disk, the size of the nucleus or of the cells forming the 

 concentric zones, the surface-markings indicating ihe shape of the 

 superficial cells, nor the early mode of growth (which, though 

 typically cyclical, sometimes approximates to a spiral), can serve as 

 distinctive characters of species ; since, whilst tiiey are all found to 

 present most remarkable difi^erences, these differences, being strictly 

 gradational, can only be considered as distinguishing individuals. 

 It thus follows that a very wide range of variation exists in this 

 type; so that numerous forms which would be uniiesitatingly ac- 

 counted specifically different, if only the most divergent examples 

 were brought into comparison, are found, by the iliscovery of those 

 intermediate links which a large collection can alone supply, to 

 belong to one and the same specific type. 



After noticing some curious monstrosities, resulting from an im- 

 usual out-growth of the central nucleus, the author proceeds to in- 

 quire into the essential character of the Orbitolite, and its relations 

 to other types of structure. He places it among the very lowest 

 forms of Foraminifei'a ; and considers that it approximates closely 

 to sponges, some of which liave skeletons not very unlike the cal- 

 careous net-work which intervenes between its fleshy segments. Of 

 the species which the genus has been reputed to include, he states 

 that a large proportion really belong to the genus Orbitoides, whilst 

 others are but varieties of the ordinary type. This last is the light 

 in which he would regard the Orbitolites complanata of the Paris 

 basin ; w hich differs from the fidly-developed Orbitolite of the 

 Australian coast in some very peculiar features (marking a less com- 

 plete evolution), which are occasionally met with among recent 

 forms, and which are sometimes distinctly traditional towards the 

 perfect type. 



" Notes on British Forami7iifera" By J. Gwyn Jeffreys, Esq., 

 F.R.S. Received June 19, 1855. 



Having, during a great many years, directed my attention to the 

 recent Foraminifera which inliabit our own shores, I venture to offer 

 a few observations on this curious group, as Dr. Carpenter, who has 

 favoured the Society with an interesting and valuable memoir on 

 the subject, seems not to have had many 023portunities of studying 

 the animals in the recent state. 



Rather more than twenty years ago I communicated to the Lin- 

 liean Society a paper on the subject, containing a diagnosis and 

 figures of all the species. This paper was read and ordered to be 

 printed in the Transactions of that Society ; but it was withdrawn 

 by me before publication, in consequence of my being dissatisfied 

 with D'Orbigny's theory (which I had erroneously adopted), that 



