VINE : CAMBRIDGE GEEENSAND. 
27 
the former species does not lend any support to this conjecture." 
I believe Mr. Sollas is perfectly justified in his conjecture that the 
two species are distinct, only from my own observations I find that 
W. IcBvis is more often la^eeniform than W. tuberculata, but I have 
found that both forms of tests are either tuherculate or free so that 
mere outline is no sufficient guide. Dr. R. Hausler, however, 
speaking of the Jurassic Trochammini says of Webhincd (p. 353 op. 
cit. above) " that though present in almost every Jurassic Zone — 
beginning with the Lias only two or three species could be 
discovered" (in the zones described by him.) One of these is 
Trochammina (Webbina) irregalaris D'Orb., but the description 
given by the author is very different from the re-description of the 
Genus by Mr. Sollas. 
TrocJunmnini (Webbinge) irregularis, D'Orb. 
" Annals " (op. cit. p. 352, pi. XV., fig. 15.) 
" Test thin, fragile, finely ^arenaceous, one or more chambered ; 
monothalamous variety consisting of a small pyriform, or almost 
hemispherical chamber ; polythalamous variety straight or irregularly 
curved &c." 
Up to the point where the description is broken off many of the 
smaller attached forms of the Cambridge Greensand and Jurassic 
agree, and even the " short stolens," are likewise present in some. 
23. — Trochammini helveto-jurassica, Hausler. PI. II., figs. 
12-I2a and 15-16. 
Annals Mag. Nat. Hist. Ser. 5, Vol. 10, pi. XV., figs. 10-11. 
Test coarsel}'' arenaceous, chambers irregular — adherent in the 
early stages of growth, free and unattached in later stages. 
Localities : Lower Malm Aargon (Hausler Jurassic) ; Cambridge 
Greeusand. 
This is the most abundant of the forms found in Mr. Jesson's 
material, and it would be quite easy, if convenient to do so, to found 
a number of varieties out of the abundance. But a few remarks 
may be advantagous. As the early adherent stages of T. helveto- 
jurassica very closely resemble WebbincB, it may be possible to mistake 
the one for the other, only that WebbincB (species described) is never 
coarsely arenaceous in its initial stages, and close observation would 
