700 DESCEIPTION OF EXGEATIN09. 



PLATE XXIV f continued.) 



Figs. 6, 7, 8 and 9. Eunolia longicornis (Ehr.) 



10. Goiiiothecium crenatum (Ehr.) 



11. Emiotia argus (Eltr.) 



12. Pinnularia (Diploneis) Didymus (Ehr.) 



13. Desmogonium Guianense (Ehr.) 



15. Pinnularia teniata (Ehr.) 



16. Himantidium monodon (Ehr.) — Two frustules conjoined, in front view. 



17. Himantidium monodon (Ehr.) — A side view, or a frustule .seen in section ; 



having but one elevation on its upper margin (dorsum, Ehr.) it derived 

 its specific name 



18. 19, 20 and 21. Arachnoidiscus Japonicus (Slmdholt.) — Fig. 18, external 



membrane, as seen when detached from the inner framework, or when 

 viewed from the outside of the shell as an opaque object ; 19, the inner 

 framework is exhibited on a black disk as an opaque object ; 20, the 

 membrane and framework united, as seen by transmitted light, 200 

 linear; fig. 21, the same, more amplified, 500 linear 



22 and 23. Campylodiscus parvulus (Smith.) — Fig. 22, a disc of valve ; fig. 23, 

 view presenting the connecting membrane, and vah-ular ridges 



24 and 25. Grammonema Jurgensii (Raits) — Fig. 24, a front and lateral view 

 of a single frustule ; fig. 25, a band of concatenated frustules 



26 and 27. Gallionella (Nageli) — A series of figures to illustrate the distri- 

 bution of the chlorophylle (endochrome). and the presence of a nucleus; 

 fig. 26 a, viewed from the base ; b, from the lateral surface. Tvso bands 

 of chlorophj'lle are seen on each side, and their section at the angles ; 

 c, from the base; fig. 27 w, seen from 1 elow. Nucleus with nucleoli 

 and sap currents ; large and small chlorophylle globules ; b, seen from 

 the side. The two lateral bands of chlorophylle are seen, and a parietal 

 nucleus vith sap-currents from it, in the centre of one side; c, an 

 individual after division, seen from the side. The chlorophylle 

 band appear only in section. Each secoudary cell has a parietal nucleus 



28 a. h- c d. Eacillaria "(Kageli.) Fig. a. viewed from the broad side. A granu- 

 lar nucleus in the centre ; fig. h. also the broad side ; an individual before 

 division. The nucleus primarily di\ided; fig. c, division complete; 

 fig. d- viewed from the base (in section ) 



29. a. b. c. d. Orthoseira Dickieii (Thwaites) ; fig. a- filament, in ordinary state ; 

 fig. b. filament, the terminal cells of which are becoming converted into 

 .sporangia ; fig. c sporangia ; fig. d. sporangial frustules becoming 

 developed from one of the halves of a pre\iously divided Sporangium, 

 (magnified 220 linear.) 



SO. a. b. Dickieia Danseii (Thwaites) ; fig. a. portion of frond (thirty-five 

 linear) ; fig. b- a part of some magnified 220 linear. In it two frustules 

 are shown ; one in front, the other on side aspect. Mr. Ealfs has sub- 

 sequently shown this to be one of the Algae, not of the Diatomeae ; not 

 a Dickieia. 



31 -a. 6. c. cZ. c. Dickieia ulvoides (Ealfs). Group a. Natural size in different 

 stages of grow th ; fig. i. frustules (navicular-bodies) highly magnified, 

 when fresh; fig. c. one when dried; fig. d. a lateral view of the same; 

 (group ('. a portion of frond, less magnified), showing the simple and 

 binate frustules. 



32. Meloseira varians (Thwaites), Gallionella, Ehr.) Filament with sporangia 

 (220 linear.) 



33. Aulacoseira crenulata (Thwaites.) — Filament with s|"orangia (220 linear) 



34. Dictyocha Tibula (Ehr ) 



35. Dictyocha tril'enestrata (Ehr ) 



