\86 Transactions of the Royal Microscopical Society. 
formation of another sporangial frustule is requisite, either by 
reason of the power of dividing becoming exhausted or from the 
diminution of the size of the frustules. 
In concluding these remarks, I beg to thank Herr Grunow for 
his kindness in permitting me to publish his valuable observa- 
tions in this Journal, thus enabling the English diatomist to 
obtain a knowledge of what other countries are doing towards 
elucidating many of the mysteries connected with the life-history 
of the Diatomaceae. — F. K.] 
Plate CXCV. 
Fig. 1 . — Mastogloia Jclineckii. 
„ 2. — „ rostellata. 
„ 3. — „ angulata var. pusilla. 
„ 4. — „ f reticulata x 400. 
„ 5. — a, „ undulata ; b, part of valve X 1500. 
„ 6. — „ bisulcata. 
„ 7. — „ minuta. 
„ 8. — a, Orthoneis crucicula ; b, forma minor. 
„ 9. — a, Amphora dccussata x 400 ; b, striae, highly magnified. 
„ 10 . — Navicula triundulata. 
„ 11. — „ fusiformis. a, valve; b, frustule. 
„ 12. — „ „ var. ostrearia. a, valve ; b, frustule. 
„ 13 . — Amphipleura Lindheimeri. 
„ 14. — „ TVciSs/oju, original specimen with abnormal terminal nodules. 
„ 15 . — Berkcleya micans. 
„ 16. — „ hospitans. a, valves; 6, ditto, with endochrome. 
„ 17 . — Schizostauron Lindigii. 
„ 18. — „ Reichardtii. 
„ 19 . — Rhoicosigma „ a, frustule ; b, valve. 
All magnified 900 diameters, excepting Figs. 4, 5 a, 5 b, and 9 a, b. 
Plate CXCVI. 
Fig. 1. — Isthmia Lindigiana. a, frustule x 200; b, lower portion of valve; c, ditto 
connecting membrane, highly magnified ; d, areolae x 1000. 
„ 2. — Triceratium orbiculatum var. elongatum. a, frustule x 200; b, c, valves 
X 400. 
„ 3. — Cerataulus la: vis var. Chinensis. a, frustule ; b, valve X 900 ; c, striae 
X 1540. 
„ 4. — Cerataulus Icevis var. x 900; 6, frustules, showing abnormal self-division. 
W ithin the smallest of the larger frustules are two minute frustules. 
