160 MESSRS. W. WEST AND G. S. WEST ON 
EUASTRUM, Zhrenb. 
18. E. exarHorHomuM, n. sp. (Pl. 9. figs. 3, 4.) 
E. mediocre, duplo longius quam latius, profunde constrictum, 
sinu angusto-lineari extremo subampliato ; semicellule truncato- 
pyramidate, angulis inferioribus subrectangularibus, marginibus 
lateralibus biundulatis elevatione medianá depressa, angulis 
apiealibus subrotundatis et leviter incrassatis, apicibus convexis 
incisura medianà profundissimá et angustissimá, serie verrucarum 
magnarum emarginatarum trium trans basin; a vertice vise 
oblongo-rectangulares, nodis tribus ad polum unumquemque, 
incisuris tribus prope medium utrobique, incisurá medianá minus 
profundá ; a latere vise ovato-oblonge, angulis basalibus rect- 
angularibus, lateribus retusis ad medium, angulis apicalibus 
rotundatis; membrana punctata. 
Long. 63-65 4; lat. 32-34 4; lat. apice. 18-20 p; lat. isthm. 
12 je; crass. 21 nz 
This characteristic species is nearest to E. quadriceps, Nordst. 
in Vidensk. Meddel. Kjób. (1869) p. 216, t. 2. f. 5, with which it 
might be compared. 
Compare also with E. Auillense, West & G. S. West, 1n 
Journ. Bot. xxxv. (1897) p. 82, t. 366. ff. 15, 16. 
19. E. siNvOosuM, Lenorm. in Ralfs, Brit. Desm. p. 85, t. 18- 
f. 5 a, b, d. 
Var. REDUCTUM, West & G. S. West, l. c. p. 83. 
Long. 46-59 u ; lat. 28-32-56 u; lat. isthm. 7°5-9°5 p; crass. 
1s u. (PI. 8. fig. 17.) 
One specimen was noticed with the same number of scrobicu- 
lations as one figured by Raciborski (Ramiet. Wydz. IL. Akad. 
Umiej. Krakow. xvii. t. 6. f. 9), but their arrangement was some 
what different. 
20. E. ansatum, Ehrenb. (Ralfs, Brit. Desm. p. 85, t. 14. 
f. 2.) 
Long. 88 u ; lat. 36 p; lat. apic. 201; lat. isthm. 15 p. 
21. E. oBEsUM, Joshua, in Journ. Linn. Soc. (Bot.) xxi. (1880) 
p. 638, t. 23. ff. 19, 20. 
