PROCEEDINGS OF SECTION C. 381 



in Girvanella which appear to be present in the former genus. Whether 

 the structures now met with in the Victorian hmestones are at all 

 comparable with those seen in SphcBrocodium remains to be proved by 

 additional and better-preserved specimens. 



Whilst discussing the algoid affinities of Solenopora, Dr. A. Brown(a) 

 expressed his opinion that the relationships of Girvanella lie with the 

 SiphonecB verticilhtcs. A valuable and interesting resume of the 

 investigations upon organisms related to algse which perform the work 

 of rock-formation, was given by Mr. A. C. Seward in 1894-.(6) The 

 subject was again discussed and summarised by the same author in 

 1898,(c) who was then inclined to provisionally place Girvanella in the 

 Cyanophycew. The present writer (d) also has recently expressed his 

 view as to the probable algoid nature of Girvanella, derived from an 

 early acquaintance with these organisms in the slides prepared by Mr. 

 Wethered, and from several other examples since collected. 



THE EVIDENCE FOR THE RHIZOPODAL NATURE OF 

 GIRVANELLA. 



Although it may appear to be somewhat belated to bring 

 forward evidence against the view that Girvanella may belong to the 

 foraminifera, this part of the subject has never been carefully criticised 

 or refuted. 



With regard to the supposed alliance of Girvanella with Syringam- 

 mina it may be briefly pointed out that, beyond the fact the latter is a 

 tubular arenaceous organism, no further comparison can be safely made. 

 Syringammina (e) possesses a test composed of loosely aggregated sand 

 grains, and is built up to form a series of branching, radiating, and 

 inosculating tubes. The morphology of the test does not easily recall 

 Girvanella, with its finelv calcareo-granular tube, which rarely branches, 

 but often reverts or coils upon itself. The large size of the tubes in 

 Syringammina (averaging nearly 1 mm. across) is an additional dis- 

 tinctive character. 



ITS ALLIANCE TO HYPERAMMINA VAGANS CONSIDERED. 



The genus Hyperammina (Brady, 1898) comprises several species, 

 most of which are remarkable for their relatively large size, having 

 arenaceous tubes of a coarse texture. The only species of this genus 

 with which a comparison can be made is H. vagans, Brady, (/) and there 

 is no doubt of the striking and mimetic resemblance which that species 

 bears to Girvanella. A closer examination, however, will show that 

 there are certain characters borne by Girvanella, apart from size, which 

 forbid our placing it with Hyperammina. or any other known rhizopod. 

 As regards dimensions, the tubular shell of the smallest examples of 

 Hyperammina vagans is slightly larger than the largest known form of 

 Girvanella. and much larger than the type form G. vroblematica. In 



(a) Brown ('94), p. 203. , (b) Seward ('94), see especially pp. 12-16. 



(c) Seward '98), pp. 124-6, p. 160. (d) Chapman ('02), p. 125. 



(e) Brady ('84), p. 242 (/) Brady ('84), p. 260. 



