G6 Messrs. Parker, Jones,, anc? Brady on the 



before his " book," were subsequent to Mr. Carter's memoir 

 on Opereulina arabica, the question really being how far the 

 apparently sweeping claim of priority in discovery is justified 

 by the researches embodied in this latter memoir. 



In Professor Williamson's paper on PoJystomella crispa we 

 have the earliest results of the microscopical investigation of 

 the minute structure of the shells of Foraminifera based upon 

 transparent sections. The calcareous shells are therein spoken 

 of as perforated by a multitude of minute foramina ; and 

 the solid umbilical nucleus is described as "pitted by small 

 but deep depressions, which may be designed to facilitate the 

 exit of pseudopodia from the innermost convolutions." This 

 appears to us the first indication of the existence of the canal- 

 system — ant'/«c?tca^«o/?,of course,rather than an actual discovery. 



Dr. Cai-penter's paper, presented to the Geological Society 

 in the following year (1849), " On the Microscopic Structure 

 oi Nummidina^ Orhitolites, and OrhitoideSy'' comes next in point 

 of time. In it the minutely tubular structure of the shell of the 

 Nummulite is described with a completeness and figured with 

 an exactness that has left little for subsequent addition. A 

 system of " canals " opening into the chambers by distinct 

 orifices, and terminating in the " interseptal spaces," is de- 

 scribed and figured ; and the specialized condition of the mar- 

 ginal portion of each whorl, so far as the perforation by a 

 smaller number of larger tubuli, is pointed out. Thus, though 

 the " canal-system " (as a system) was not traced in its 

 entirety, owing to the research being based upon fossil speci- 

 mens alone, a large proportion of the facts necessary for its 

 establishment were con-ectly laid down. 



In 1850 Prof. Williamson made a further contribution to 

 the subject in his memoir " On the Minute Structure of the 

 Calcareous Shells of some Eecent Species of Foraminifera," 

 which contains chiefly the record of investigations on the 

 structure of two species of Amphistegina^ and on a so-called 

 Nonionina from the Philippines (really an Opereulina) , together 

 with other matters. Not only is the parallel tabulation in the 

 chamber-walls herein described, but also the " canal-system " 

 of the marginal portion of the spire, the large radiating tubes 

 (of Dr. Carpenter's paper) being shown to be part of a plexus 

 of canals communicating with the interseptal spaces, which 

 plexus is minutely described and figured. The connexion of 

 the interseptal spaces with at least one continuous tube in 

 each of the spiral parietes separating contiguous canals is de- 

 monstrated ; in fact Professor Williamson had, in 1850, made 

 out almost the entire canal-system of the Opereulina type. 



The following year the same able investigator communi- 

 cated a third memoir to the Microscopical Society, " On the 



