outward ; keel with prominent angle, forming together with the endocarp two short 

 blunt spines at the base, reaching to the style ; endocarp fairly hard, sculpture irregular 

 cells elongate circumferentially. 



Length (including style) 2.4 mm., breadth 2.2 mm. Reuver. 



POTAMOGETON Sp. 9. 

 PI. II, fig. 10. 



Nut irregularly orbicular very broad and rounded above incurved below on 

 ventral side, attachment basal ; endocarp with a small apical spine behind the style ; keel 

 very broad scarcely angled. 



Length 2 mm., breadth 1.9 mm. Swalmen. 



The single specimen here described seems to represent a different species; but it 

 is too much distorted for fuller description. 



POTAMOGETON Sp. 10. 

 PI. II, fig. 11. 



Nut obliquely obovate inflated, ventral margin gibbous above incurved below, 

 dorsal margin semicircular, attachment terminal, central depression small and deep; 

 style apical, short and conical; keel conspicuous but blunt. 



Length 1.9 mm., breadth 1.7 mm. Reuver. 



We have only a single specimen belonging to this well-marked species. The 

 endocarp is exceptionally thick, hard, and broadly pointed at the apex. 



NAJADACEAE. 



NAJAS. 



This genus is represented by four well-marked species, three of which are extinct 

 and unknown in other deposits. Najas minor, which is abundant in the Teglian is 

 unknown in the Reuverian. We have consulted Dr. Rendle as to the new species. 



NAJAS MARINA Linn. 

 PI. II, figs. 12—14. 



Seeds small but indistinguishable from some forms of the recent plant, and like 

 them varying considerably in width. In figs. 12 and 13 we have illustrated the variation 

 in size and shape at the same locality; fig. 14 shows the interior of the testa with the 

 loose sac*like tegmen. 



Fig. 12 length 2.7 mm., breadth 1.4 mm.; fig. 13 length 3.6 mm., breadth 

 1.6 mm. Reuver, Swalmen. 



This species is common at Reuver and Swalmen, but has not yet been found at 

 Brunssum. It occurs also abundantly in the Teglian and Cromerian. 



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