MR. W. JOSHUA ON BUBMESE DESMIDTE*. 645 



11. Cosmaeium, Corda. 



C. Ettastbon, n. sp. (Plate XXIV. figs. 30-34.) 



C. mediocre, ovatum, l|-l^-plo longius quam latum, apicibus 

 non truncatis, prof unde constrictuin : strictura lineari aut an- 

 guste cuneata : semicellulis semirotundatis : angulis inferioribus 

 fere rectis, apicibus ovatis : membrano crasso, dilute pallido- 

 flavescente (colore intensiore in centro zonali cellulae), papillis 

 magnis, basi expansis, stellato-dispositis. Longit. 65-95 p, latit. 

 47-50 ju: crassit. 27-33 /x : isthmi latit. 15 ft. 



Medium size, oval, 1| to 1| times longer than wide; ends 

 not truncate, deeply constricted ; stricture linear, or narrow 

 wedge-sbaped ; semicells semicircular ; lower angles nearly 

 straight ; apices oval ; membrane thick, very pale yellow, deepen- 

 ing in zonal centre of cell ; papillae large, with spreading base, 

 and showing a clearly defined quincunx arrangement with stellato- 

 cuneiform rays in oblique light. Smaller and more globose than 

 C. tholiforme, Cohn, to which it comes nearest. Length 65 //-90 /i ; 

 breadth 47-50 fi ; thickness 27-33 tx ; width of isthmus 15 ft. 



C. TFEQIDUM, Breb. 



C. geanatum, Breb. 



C. Debaetii, Arch. 



C. PULCHERitiMUH, Nbrdst. A small var. 



C. CTTCTTBBITA, Breb. 

 C, CEENATUM, Balfs. 



C. capax, n. sp. (Plate XXV. fig. 8.) 



C. magnum, cylindricum, duplo longum quam latum, medio vix 

 constrictum, annulo marginali ad punctum junctionis : lamellis 

 chlorophyllaceis multis, curvatis, granulis amylaceis passim di- 

 spersis: membrano pallide fusco, regulariter minute punctato. 

 Longit. 165 /i, latit. 90 /u. 



Large, cylindrical, twice as long as wide ; middle scarcely con- 

 stricted, with a marginal ring at point of juncture. The chloro- 

 phyll-plates of contents many and curved, with starch -granules 

 scattered throughout; membrane pale brown, regularly and 

 minutely punctate. Length 165 fx; width 90 /i. 



C. OBSOLETTTH, Hantzsch. 

 C. SMOLANDICUM, Lund. 



C. Cucumis, Corda. 



C. Botettis, Menegh., var. indicum, n. var. (Plate XXIV. 

 fig. 19.) 



C. semicellulis profunde constrictis, centro non inflatis, granulia 



