part 2] GEOLOGICAL HISTORY OF THE GENUS STRATIOTES. 131 



Marie ochre-mine, Ringsberg, near Frielendorf (Hessen), have been 

 described by Dr. Menzel as Folliculites JcaltennordJieimensis var. 

 minima (72) ; these he regards as distinct only in their small size 

 from F. Jcaltennordheimensis. I could not examine the specimens; 

 but, judging from the figures, which showed them to have a 

 decidedly sigmoidal outline, I thought it probable that they were 

 small examples of S. websteri. 



From Dr. Menzel's letters I learnt that S. Jcaltennordheimensis 

 and S. websteri had been united under the former name. One 

 would not expect S. toebsteri in Miocene ckiys, unless it were 

 remanie, and it certainly occurs in the underlying Oligocene of 

 Hessen. This problem can only be solved by the field geologist. 



7. Stratiotes tuberculatus E. M. Reid. (PI. V, figs. 16-17 

 & PL VI, figs. 12-16, 28.) 



1920. S. tuberculatus (E. M. Reid 71). 



Seed rounded-oblong or ovate, hooked at the base, scarcely 

 flattened ; keel moderately broad to narrow, convex to the exterior, 

 not merging into, but continued round, the base of the collar as 

 far as the micropyle ; collar moderately large, usually conspicuous ; 

 testa thick, woocly, ornamented with narrow elongate tubercles 

 arranged in longitudinal rows and sometimes forming longitudinal 

 ridges, present also on the keel; pitting fine, conspicuous over the 

 whole surface. The outline, seen from the interior, is often, though 

 not invariably, crested and serrate ; micropyle usually basiventral, 

 rarely sub-basal, oblique, horizontal, or seldom recurved, narrowing 

 markedly towards the exterior ; hilum basilateral ; raphe diagonal, 

 passing across the length of the keeled dorsal margin, entering the 

 seed-cavity below the apex ; cells of the inner side of the keel 

 long, narrow, and parallel-sided, not digitate, immediately within 

 the cell-cavity becoming broader, more irregular, and digitate. 



Dimensions. — Length~8mm. ; breadth =3 "25 mm. (largest). 

 Length:=5 , 5 mm. ; breadth = 3"25 mm. (smallest). Specimens of 

 average size vary from 7 5 to 6 mm. in length, and from 3 "75 to 

 3 mm. in breadth. 



Horizon. — Upper Miocene and Lower Pliocene. 



Localities. — Miocene (Pontien) lignite of Chambeuil, Murat 

 (Cantal) ; Pliocene lignite of Pont-de-Grail, St. Clement (Cantal). 



Affinities.—^, tuberculatus is very closely related to S. Jcal- 

 tennordheimensis ; they agree very nearly in the character of the 

 external sculpture, but the form of S. Jcaltennordheimensis is on 

 the whole more slender, and its keel is not continued round the 

 base as in S. tuberculatus. Internally, the species may be dis- 

 tinguished by the character of micropyle and raphe : in S. tuber- 

 culatus the micropyle is commonly horizontal or recurved, while 

 in S. Jcaltennordheimensis, though usually very oblique, it never 

 becomes horizontal or recurved. In S. tuberculatus the raphe is 

 diagonal throughout its course and it approaches the seed-cavity 

 -very gi-adually, entering it below the apex of the dorsal side. In 



