630 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 17, 



lules are in contact tliroughout their entire length, and arise from 

 a single, internal, coenosarcal canal, which " occupies the cen- 

 tral portion of the stipe." A sohd axis is sometimes present, 

 but appears to be absent in some species. The test is reticulate, 

 or punctate. According to Barrande and Hall, the section of the 

 frond shows that it is triangular in shape ; but in the specimens 

 from the Coniston Flags (all beautifully preserved in relief) the 

 frond is shown to have the form of a flattened cyHnder, elliptical in 

 transverse section, the flattening not seeming to be in any way due 

 to compression, since it is invariably in a direction at right angles 

 to that of the cellules. 



Retiolites Geii^itziantis, Barr. PI. XIX. figs. 19, 20. 



Gladiolites Geinitzianus, Barrande, Grapt. de Boheme, pi. 4. 

 figs. 16-33. 



Frond known by fragments only, which show neither the prox- 

 mal nor the distal extremity. The breadth of the frond in its 

 widest portion is from -^ up to -^ of an inch, gradually diminish- 

 ing towards the base. The cellules are disposed on each side of 

 a common canal, there being apparently no solid axis. They are 

 in the form of quadrangular tubes arranged alternately along op- 

 posite sides of the frond, in contact throughout their entii^e length, 

 from 25 to 30 in the space of an inch, and forming an angle of 

 about 60° with the general axis of the frond. The cellules do not 

 meet in the centre, but leave a vacant median space, into which the 

 ceU-partitions do not enter. The cell-mouths are nearly in a line, 

 subparallel as regards the median line of the frond, and forming an 

 angle of about 120° with the inferior cell-waUs. The test is covered 

 with small, rounded, often umbilicated reticulations. 



Loc. Coniston Flags of Broughton Moor in Furness. 



Retiolites peelattjs, Xich. PL XIX. figs. 21, 22. 



Frond attaining a width in the fully developed portion of not 

 less than ^ of an inch. The total length, though unknown, must 

 have been very considerable, as one of my specimens reaches a 

 length of 2 inches without showing any signs of contracting to- 

 wards either extremity. The cellules are in contact throughout 

 out their entire length, the ceU-mouths being slightly convex, and 

 parallel with the median line of the frond. The cell-partitions are 

 very faintly marked. There are plain indications of a very delicate 

 solid axis. The entire impression is crossed in every direction by 

 interlacing reticulated threads, which leave numerous small lacunae 

 or interspaces between them. 



This extraordinary Graptolite, in the venose character of its reti- 

 culation, is undistinguishable from Retiolites venosus of Hall (Pal. 

 N. York, vol. ii. p. 40, pi. A. xvii. fig. 2). It differs, however, in 

 apparently wanting the emarginate lateral borders and the mucro- 

 nate extensions of the ceU-partitions which distinguish the latter ; 

 and it is even more readily separated by its comparatively gigantic 



