352 Dr. R. Hiusler on the dvochammuee 
The shells erroneously described as Rotalina. suprajurensis, 
R. macrocephala, R. universa, h. pygmea represent the principal 
Jurassic modifications. 
T. inflata is a common species throughout the whole Malm, 
and it is the most abundant arenaceous form in the Bathonian 
zone of Rhynchonella varians. 
5. Trochammina globigerinotdes, sp.nov. (Pl. XV. figs. 8, 9.) 
The few specimens are, as a rule, found in unfavourable 
preservation, owing to the minute size and thinness of the 
delicate shells. 
Test rotaline, inflated; superior surface slightly convex, 
inferior excavated at the umbilicus. Convolutions few ; oldest 
chambers small, regularly increasing in size; last four seg- 
ments large, globular, of nearly equal size. 
Test very thin, finely arenaceous, the hyaline sandy con- 
stituents imbedded in a subtransparent or almost glass-like 
colourless cement. Surface more or less rough. 
T. globigerinoides is easily distinguished by its thin, 
almost hyaline test, and the globigerine mode of growth, not 
attempted by any other Jurassic species. 
6. Trochammina helveto-jurassica, Hiusl. 
(BLOX. figs. 10511.) 
Test free, crozier-shaped, spiral only in its earlier stage, 
afterwards straight. Spiral part resembling 7. inflata, com- - 
posed of globular, regularly increasing chambers arranged in 
convolutions. Superior surface convex ; first chambers often 
irregularly heaped or corroded ; inferior umbilicated. 
Rectilinear younger part consisting of few broad segments 
of nearly equal size. 
Test finely arenaceous, cement generally subtransparent or 
ferruginous. Surface rough. Long. 0°6 millim. 
This interesting species holds a similar position among the 
rotaline Trochammine as T. centrifuga, Brady, amongst the 
Ammodisct, T. planorbiformis among the Webbine, and T. 
lituiformis among the simpler septate Z’rochammine. 
The species is very rare, and generally in a bad state of 
preservation ; no aperture is visible, for this reason. Imper- 
fect specimens with the oldest chambers removed were described 
as Lituola (Haploph.) helveto-jurassica. 
7. Trochammina vesiculata, Uhlig*. 
This species, described by Uhlig from the same zone, is not 
* Uhlig, “D. Jurabild. v. Briinn,” Beitrage z. Pala&ont. Oest.-Ung. 
vol. i. part iii. p. 181, pl. xvi. figs. 4-6, and Neues Jahrbuch f. Min. 1882, 
p. 155. 
