Mr. M. J. Carter on Ramulina parasitica. 101 



diameter. Diagi-ammatic sketch taken from a slice of Orbito- 

 lites Mantelli, var. Theobaldi, reduced to transluceut thinness 

 and cut a little obliquely, so as to show part of the central plane 

 overlain by the crust, a, cells of the central plane ; b, cells of 

 the crust ; c, globular lobes of the Ramulina conhned to the 

 cells of the central plane and joined together by a common 

 stolon ; e, the zigzag form ; //, lobes in the " free state " 

 more or less multiangular and joined together by stolons, 

 presenting in the aggregate a reticuliform character like that of 

 the capillitiuiu of some of the Mycetozoaj </, lobes united to- 

 gether directly. 



Fig. 2. The same. Portion in the " free state," more magnified, to 

 show : — a, the lobe or chamber ; b, the stolon -,000, tubuli pro- 

 jecting I'rom the surface of the chamber ; d, chambers below the 

 surface unfinished ; ee, two cliambers united together. Taken 

 from the polished surface of a fragment of the rock containing 

 the said Orbitvlite.<, where the chambers of the Ramulina 

 appear at different depths in the transparent crystalline matrix. 

 (Un most of the chambers the tubuli are omitted for perspicuity 

 and to save trouble in drawing.) 



Fig. 3. The same. Single chamber, more magnified, to show the tubuli 

 and their position on the surface in situ (fig. 3 a). Fig. 3 b 

 represents a small fragment of the surface of the chamber mag- 

 nified to the scale of l-48th to l-3000th of an inch, to show that 

 the bases of the tubuli are respectively situated in the centre of 

 grains of calcite, which appear to have a polygonal shape. 



Fig. 4. The same. Two chambers, much magnified. Taken from the 

 surface of the polished fragment, where their upper parts have 

 been ground off, thus showing a, the thinness of the wall, and 

 A, the reticulated structure in the interior of the chamber, at 

 the same time. 



Fig. 5. The same. Group in which both sides of the lobe, a, have been 

 ground down, thus again showing the reticulated structure 

 of the interior, but by transmitted light ; b, one in which 

 the section has not gone below the surface, showing the trun- 

 cated ends of the tubuli ; c, unfinished lobe. Taken from a 

 microscopic slice which had been reduced to transluceucy. 



Fig. 6. The same. Five cells of the central plane obliquely cut across, 

 so as to show the structure of the globular lobes which they 

 respectively contain gradationalhj. a, cells of " central plane ; " 

 b, opaque state of " globular lobe " uncut ; 0, showing indis- 

 tinctly traces of the (i") reproductive bodies which it contains; 

 d, the same more distinct ; e, the same still plainer ; /, the 

 thinnest section of all, in which the reproductive elements 

 appear to consist of spherical cells, ^, imbedded in the reticu- 

 lated tissue ; A, stolon. All the parts of this illustration are 

 magnified to the scale of l-48th to 1-COOOth inch and taken 

 from a mounted microscopic slice. 



