1 H < "I UN8 a\i> III RVEY. 



Var. patenti88IMi m (Harv. Farlow, L881, p. 138; C. aracknoideum 

 var. patentisrimum Harvey, l s ~>:;. p. 217, PI. XXXIII. B, Heron 

 Bay, Jan., Hervqy. The frequent wide forkinga give a habit quite 

 different from the typical form, but there is agreement in essentials. 



Y;ir. kBACHNomBUM kg. J. G. Agardh, L851, p. 117; L876, p. 94; 

 I\ B.-A., No. 2098. C. aracknoideum Harvey, L853, p. 217; C.dia- 

 phanum var. aracknoideum Agardh, 1824, p. L34. On Cyma 

 and various algae, Grasmere, Feb., Harvey. A very slender and 

 delicate form, but otherwise like the typical form. 



Var. ptgmaeuh (Kutz.) Hauck, L888, p. WO; P.B.-A.,No. 2193; 

 Hormoceras pygmaeum Kiitzing, L862, p. 23, PL I. XXV. On Codium 

 decorticatum, Cooper's Island, Aug., Collins. With tetraspores. 



2. C. cruciatum sp. nov.; P.B.-A., No. 2192. Minuta, ad 

 algas alias repens; filamentis prostratis circa 200 u diam., cylindricis 

 vel ad nodos leviter constrictis, rhizoidis unicellularibus incoloratis 

 affixis; filamentis erectis passim ad nodos evolutb; apice filamenti 

 prostrati assurgente, in filamentum erectum transformato; cellulis 

 inferne circa .'J diam. longis, superne brevioribus, prope apicem diam- 

 etro brevioribus; ramulis penultimis 80 LOO/i diam.; ramis repetite 

 dichotomis, cellulis cylindricis vel plus minusve ad nodos constrictis; 

 apicibus forcipatis; corticatione cellulis sensu filamenti elongatia 

 constante, [rregulariter positis, zonam arctam formante margine 

 inaeqUali. Protoplasms cellularum inferiorum subcylindricum, 

 superiorum subsphaericum, fasciis tenuissimis longitudinalibus notata, 

 raro anastomosantibus, nee longitudinem cellulae aequantibus, 

 plerumque spatio latitudinem fasciae aequali separatis. Tetra- 

 sporangiis ovoideis, circa 50X35/*, membrana 6/i crassa non in- 

 clusa, 1 1 ad nodum, cruciatis, niodo regulariter, modo decussate; 

 aut singulis ad nodum. seriem externalem longitudinalem formantibus, 

 aut pluribus nodum circumdantibus; dimidio sporangii extra cortieem 

 emergente. Plate IV, figs. 27 28. 



Minute, creeping on other algae; prostrate filaments of about 

 200 U diam., cylindrical or slightly constricted at nodes, attached by 



unicellular, colorless rhizoids, issuing from the node-; erect filaments 

 occasionally arising at node-; apex of prostrate filament becoming 



erect and assuming the character of an erect filament; cells about 

 3 diam. long below, diminishing towards the apex, to less than one 

 diam.; penultimate branches 80-100 u diam.; branches repeatedly 



forking, cells cylindrical or with nodes more or less constricted; 

 apices forcipate; corticatioo consisting of cells elongate in the direc- 

 tion of the filament, in no definite order, hand narrow, edge Uneven. 



