SOME KOETH AMEKICAN DESMIDIE.E. 233 



11. Gymnozyga delicatissima, Nordst. in Wittr. et Ts^rdst. Al?. Exsic. in obsorv. ad 

 no. 803 ; Lagerli. in Notarisia, anno iii. (ISSS) fasc. 12, p. .595. [Bamhusim, deli- 

 catissima, Wolle, Desm. U.S. p. 25, pi. 1. fi^^s. 22-2i.) 



Long. 15-5-18 fx ; lat. 6-5-7 ai. (PI. XII. fig. 22.) 



The examples noticed by ns had shorter cells tli an Wolle's, the length liardly ever being 

 three times the breadth. The two median hands were quite delicate in their character. 



Genus Desmidiuji, Agardh. 



12. D. Aptogoktjm, Breb. Alg. Falaise, p. 65, t. 2. {Apfogomim Desmidium, a, Kalfs, 



Brit. Desm. p. 64, t. 32. fig. 1.) Zygosporte subglobosjB vel late ellipticac, glabrae. 

 Long, zygosp. 22-27 ti ; lat. zygosp. 20-25 m. (V]. XII. lig. 24.) 

 The cells of the conjugated filaments were all somewhat disjointed. 



Var. Ehrenbergii, Rabenh. Fl. Europ. Alp. iii. p. 154. {Odontella Desmidium, 

 Ehrenb. ; Jj^toffoutfm diagonnm, Delp. Spec. Desmid. Subalp. p. 76, t. 3. figs. 6-10.) 

 (PI. XII. fig. 23.) Forma cellulis latioribus brevioribusque ; a vertice visis oblongis 

 cum lateribus rectis et apicibus inflatis. 

 Long. cell. 14-5-15-2 fx ; lat. 34-35 u. ; lat. isthm. 25-265 ju ; crass. 7'5 fi. 

 When seen in front view this so much resembles Desmidium Aptogonum, that it must 

 1)6 but a variety of it. Aptogonum diagonnm, Delp., appears to be only a form of this 

 variety, though it differs from what we have seen in its longer and thicker cells. 



13. D. CYLiKDEiCLM, Grev. Scot. Crypt. Fl. p. 292 et tab. {Didijnwprium Grevillei, 



Kuetz. Phycol. General, p. 166 ; EaKs, Brit. Desm. p. 57, t. 2.) 

 A figvire is given of a zygospore of this species (long. 43 jn, lat. 36 (U<). (PI. XII. fig. 29.) 

 Var. OBLiQUUM, nov. var. (PL XII. fig. 30.) Var. semicellulis a vertice visis latere 



uno convexis, latere altero valdissime convexis fsemicircularibus). 

 Lat. 61 ^ij ; crass. 49 (Jj. 



14. D. cOAiiCTATUM, Nordst. Freshw. Alg. of New Zeal. & Austr. p. 25, pi. 2. fig. 3. 

 Long. 22-32 ^ ; lat. 37-41 /t ; lat. apic. 15-17 ^l ; lat. isthm. 28-30 ax. 



15. D. QUADEATrM, Nordst. Bidrag Sydlig. Xorges Desm. p. 19, fig. 24. 

 Long. cell. 14-17 i^ ; lat. 21-23 m lat. isthm. 18-19 ,x ; crass. 17-5-18 ^. 



A few exactly typical filaments of this were observed, and as Wolle's figure (Desm. 

 D.S. pi. 49. fig. 5) is not a representative one— the lateral incisions of the cells 

 especially being too deep — we give one (PI. XII. fig. 25). 



15*. D. ^DQiJALE, nov. sp. D. a D. quadrato differt cellulis majoribus, a fronte et a latere 

 visis latioribus, zygosporis globosis, undulato-nodulosis. (PI. XII. fig. 28.) 



a. ELLiPTiCA (PI. XII. fig. 17) cellulis a vertice visis subcircularibus et subporrectis 



ad polos. 



b. TRiGONA (PI. XII. fig. 26) cellulis a vertice visis trigonis, lateribus convexis et 



angulis subporrectis. 

 Long. 17-19 /«.; lat. 29-31^; lat. apic. 21-22 ^: lat. isthm. 28 ^; diam. zygosp. 



25 m. 



