276 



Dr. W. B. Carpenter. 



[June 14, 



June 14, 1883. 



THE TREASURER in the Chair. 



The Presents received were laid on the table, and thanks ordered 

 for them. 



Dr. James Crichton Browne, Surgeon-Major George Edward 

 Dobson, Dr. James Matthews Duncan, Mr. Charles Edward Groves, 

 Professor Arnold William Reinold, and Mr. John James Walker were 

 admitted into the Society. 



The following Papers were read: — 



I. " Researches on the Foraminifera. Supplemental Memoir. 

 On an Abyssal Type of the Genus Orbitolites ; a Study in 

 the Theory of Descent." By W. B. Carpenter, C.B., M.D., 

 F.R.S. Received May 31, 1883. 



(Abstract.) 



This paper is supplemental to the series of Memoirs formerly pre- 

 sented by the author on the structure of certain of the higher forms 

 of the group of Foraminifera ; in which he laid down the new prin- 

 ciples of classification afterwards worked out by him, in conjunction 

 with Messrs. W. K. Parker and T. Rupert Jones, in his " Introduction 

 to the Study of the Foraminifera;" and especially to the first of those 

 memoirs (" Phil. Trans.," 1856), which consisted of a Monograph of 

 the genus Orbitolites, and of some general doctrines deduced from the 

 study of it as to the Range of Variation in Species, a question which 

 was much occupying the attention of philosophical naturalists. The 

 subsequent publication of Mr. Darwin's " Origin of Species " having 

 led him unhesitatingly to adopt the principle of " Descent with 

 Modification " or " Genetic Continuity," he had applied it to the con- 

 struction of a pedigree of the Orbitoline type ; between the smallest 

 and simplest, and the largest and most complex of which, he had 

 shown in his first memoir that such " continuity " could be clearly 

 traced out. 



Starting with the very simplest type of Foraminiferal organisation 

 — a minute globular or pyriform monothalamous shell, with a single 

 orifice, enclosing a particle of sarcode — he showed (1) that the exten- 

 sion of such a particle into a spirally-coiled sarcodic cord, invested by 

 a porcellanous shell, becomes a Coriiuspira ; (2) that a constriction of 

 this cord at the points at which additions are made to the length of 



