2 



cytiodermate leve ut margarita nitente. Zygosporis sphaericis, spinis 

 elongatis apice bifidis obsitis. Diam. .0009" — .001". 



Hab. Splitrock Pond, New Jersey. 



This plant might pass for a variety of C. venustum^ Breb., or C 

 Nae^elianiim^ IJreb., had the end no central inflation. C phaseoliis^ 

 Breb. possesses the inflations, but is entire. 



Cosmarium pectinoides, Wolle. (Plate VI, Fig. 8, front view; 8^7, 



side view). Described in Bulletin, Vol. VI., p. 122. 



This may be a variety of C. pulcherrimum, Nordst. It differs 



from that species, however, in the more numerous radiating rows of 

 granules. 



Cosmarmm dentatum, Wolle. (Plate VI, Fig. 9). Described in 

 Bulletin, Vol. VI., p. 122. 



A fine, distinct species. It approaches C, Brehissonii, Menegh., 

 but is more than twnce the size. It exhibits the conical granules, like 

 teeth, on the sides of the cells. The ends are devoid of teeth. Not 

 infrequent in Pennsylvania and in New Jersey. 



Cosmarium Donnellii, ;^. ^/. (Plate VI, Fig. 10, front view; 

 \oa, end view), C. mediocre, plerumque fere tarn longum quam la- 

 tum, suborbiculare, sinu anguste-lineari; semjcellulis subsemicircu- 

 laribus, dorso plus minus depressis, margine circiter t8 margaritis 

 ovalibus, in series singulas, composito. Diam. et lat. .0015*' — .ooi8'\ 

 Hab. Ponds, Florida. Collected by Capt. J. Donnell Smith, 1879. 



This species comes nearest C. vionoinazn77t, Lund, but is a dis- 

 tinct form. 



^ Staur.\strum odontatum, 71. sp, (Plate VI, Fig. it front 

 view; i la, end view). St. magnum, tam longum quam latum; semicellu- 

 lis a fronte visis, quadrangularibus angulis superioribus in cornu 

 gracile elongatis, incurvis vel rectis, marginibus plus minus profunde 

 serrato-dentatis in apicem furcatum productis; angulis inferioribus 

 dentibus armatis, a vertice visis quadriradiatis. Diam. sinerad. oooS" 

 —.001" ; cum rad., .0016"— .003'' ; long, .0016"— .0018''. 



Hab. Splitrock Pond, New Jersey, July, 1880. 



This plant has much in common with some varieties of Si. g7'acile, 

 Ralfs, but is more robust, has quadrangular semicells, is larger, and 

 is furnished with teeth near the sinus. 



Staurasfru77i cu7ieatu77i^ Wolle, f^ Plate VI, Fig. 12 j. Described 

 in Bulletin, Vol. VI., p. 123. 



Staurastrum botrophilum, «. j/. (Plate VI, Fig. 13, front 

 view; 13^, side view; 13^, end view). St. mediocre, paulo longius 

 quam latms, distincte granulosum; granulis in series regulares ordi- 

 natis; a fronte, semicellulis triangularibus, angulis inferioribus rotun- 

 datis subito in dorsum late truncatis, a lateribus, late ellipticis di- 

 vergentibus, a vertice, triangularibus. Diam, .0015''— .0016". 



Hab. Swampy places near Bethlehem, Pa. 



This form belongs to a class like Si.pyg77iaeu77i^ Breb;, St, ptuictu- 

 latian, Breb., Sl rugulosm/i, Breb.. etc., but is separated by the Cos- 

 marumi^ike, truncate form as seen in front view. 



Staurastrum Pringlei, «. sp (Plate VI, Fig. 14. quadrangu- 

 lar-end view; i^a, front view; 14^, side view; 14^% triangular-end 

 view> St. parvum, distincte granulatum, tam longum quam latum, 



