BY G. 1. PLAYFAIR. 527 



Var. TENUissiMUM, n var. (PI. liv., f.5). 



Forma minuta, angustissima ; lateribus parallelis ; apicibus 

 truncatis nee incrassatis; cellulis ssepe in filamentis consociatis. 

 Merabrana Isevis, glabra. Endochroma homogenea in baculo 

 unico (ut videtur) ordinata, in extremis ssepe granulis singulis 

 instrueta. Pyrenoidibus nullis. 



Long. 54-112; lat. If 2^ /a. 



Present in all the filter-samples, frequent in June. 



All the forms of Gonatozyyon belong to a single species, the 

 nomenclatui'al type heingGon. Kinahani, since Doc.asppritm Ralfs, 

 contains two different forms. The thi-ee principal forms are quite 

 common round Sydney, and are always found in the same water. 

 Compare W. ii G. 8. West, Monog. Brit. Desm., PI. i., figs.l and 5, 

 with PI. ii., figs.l and 3, the outlines are exactly the same in each 

 case. I have shown(aw<<?a 1910), in connection with the forms of 

 Bocidiiim, that no specific distinction can be deduced from the 

 chai-acter of the membrane, even granulate and smooth being 

 found in the same cell. Polym. it Life-Hist., PI. xi., f.3, and 

 PI. xiv., f.ll. 



Genus Penium Breb. 



P. poLVMORPHUM var. CYLiNDRACEUM, n.var. (PI. liv., f.t)). 



Forma angustior cylindracea; lateribus pai-allelis; apicibus late- 

 rotundatis. 



Long. 34-36; lat. 1 4 /a. 



Var. MooREANUM (Arch.) mihi. (PL liv., f.7, 8;. 



Long. 18-24; lat. 10-12 /x. 



Suture sometimes evident, sometimes not. The shape varies, 

 with growth, from a regular ellipse to the form of the type. Syn. 

 P. Mooreanum Arch. 



Var. MiNUTissiMUM(Nord.) mihi. (PI. liv., f.9, 10). 



Long. 13-16; lat. 8-9 /x. 



Syn. P. minutissirmim Nord., Norges Fersk. T.i., f.21. 



Var. TuRNERi, mihi. (PI. liv., f.ll). 

 I^ng. 9-12; lat. 5-7 /x. 



