RHABDAMMININAE 331 



67. Tholosina vesicularis (Brady). 



Placopsilina vesicularis, Brady, 1879, etc., RRC, 1879, p. 51, pi. v, fig. 2; 1884, FC, p. 316, 



pi. XXXV, figs. 18, 19. 



Tholosina vesicularis, Rhumbler, 1903, ZRR, p. 227, fig. 53. 



Seven stations: 235; WS 76, 77, 213, 215, 225, 243. 



Probably generally distributed wherever conditions are suitable. It often occurs in 

 enormous numbers, particularly at WS 225 and 243, where it encrusts the stones. 



68. Tholosina vesicularis var. erecta, Heron-Allen and Earland (Plate XVII, figs. 7, 8), 



Tholosina vesicularis var. erecta, Heron-Allen and Earland, 1929, etc., FSA, 1929, p. 325, 

 pi. i, figs. 7, 8. 



Six stations: WS 77, 213, 221, 225, 242, 243. 



The characters of the variety are the same as those given by Brady for the species, 

 but the tubular extensions, instead of being attached to the surface of the stone, are free 

 and project above the organism like factory chimneys. Occasionally the tubes fork, a 

 feature which Brady mentions in connection with the type, but which is, in our experi- 

 ence, very rarely seen. 



The variety favours depressions and cavities in stones, and is accordingly less convex 

 than the type. In many specimens it forms merely a flat arenaceous membrane enclosing 

 a cavity and surrounded by vertical tubes as shown in fig. 8. The size is variable, but 

 specimens have been seen up to 4 mm. in diameter. 



T. vesicularis is abundant and widely distributed in the Falkland area, but the variety 

 erecta has so far only been observed at those stations where the presence of many de- 

 composing rock fragments favoured its growth. Probably it occurs in other suitable 

 localities, as fragments of similar tubes have been observed at many stations which, until 

 the discovery of the entire organism, were regarded as fragments of Psammatodendron , 

 Norman. 



Sub-family RHABDAMMININAE 



Genus Jaculella, Brady, 1879 



69. Jaculella acuta, Brady. 



Jaculella acuta, Brady, 1879, etc., RRC, p. 35, pi. iii, figs. 12, 13; 1884, FC, p. 255, pi. xxii, figs. 

 14-18. 



Two stations: WS 99, 217. 



Single specimens. 



70. Jaculella obtusa, Brady. 



Jaculella obtusa, Brady, 1882, FKE, p. 714; 1884, FC, p. 256, pi. xxii, figs. 19-22. 

 Jaculella obtusa. Goes, 1894, ASF, p. 20, pi. iv, figs. 87-9; pi. v, figs. 90, 91. 



Two stations: WS 217, 219. 



A number of coarsely arenaceous specimens at WS 219, and one entirely constructed 



of spicules at WS 217. 



