16 42 Proceedings of the Royal Irish Academy. 



diameter, spherical, more rarely elliptic, in cubical families; eell- 

 contents blue-green." I perhaps ought also to add that I had 

 described this plant in my manuscript as a new species of Merismo- 

 pedium, necessitating an alteration in the definition of the genus : 

 this was some time before I came across a description of Eucapsis, so I 

 think it may be of interest to publish just what I had written before 

 I knew of Eucapsis : — " Merismopediwm cubieum sp. nov. Familiis 

 e cellulis 64 compositis, 4 longitudine, 4 latitudine, et 4 in altitudine, 

 in strato umcoso distiucto et hyalino, cellulis eoufertis et angulato- 

 globosis, eontentis aeruginosis, 5-6 - 6ju lat. The specimens seen 

 consisted of four families, held together by their gelatinous invest- 

 ment and arranged in a square. The genus Merismopedhmi will 

 require amending to include this species which had certainly divided 

 in three directions of space as in the bacterial genus Sarcina," 

 ~Holopedium irregulare (Lagerh.) Hansg. — C, 2-2', u. 

 Tetrapedia reinschiana Arch. — Cr, D, DL, L, VL, 0. 



Fam. Chamaesiphonaceae. 

 "Chamaesiphon incrustans Grun. — L, on Cladophora crispata : AS, C ; VL : D. 

 on Copepods. 

 *curvatus Xordst — DL, 3-4/t broad, 18-24// long. 



Order HORMOGOXEAE. 

 Sub-Order Psixoxe:mateae. 



Fam. Oscillatoriaceae. 

 Sub-fam. Oseillatorieae. 

 Oscillatoria Agardhii Gom. — C, in many places, 36-4// broad. 2// long, also 

 4'5— 5/u broad, cells i to | as long as broad, all distinctly capitate ; 

 M, G« broad, 3-4// long ; S, 4 - 2// broad, f as long as broad. 



amphibia Ag.— C, W; M, 2*5// broad, 3/i long; CP, 2v>-3// broad, 4// long : 

 S ; Ac, 2'6-34/n broad, 3*6-4// long. 



"angustissima TV. & G. S. "West. — C, 0-6-06G// broad, in another place 

 0*7// broad, 1*1// long. 



formosa Bory. — CP, 5-5*5 broad, average length 3-4//. 



limosa Ag.— M, 11// broad ; C, 16-17// broad, cells six times shorter than 

 broad; L, 14-15// broad, cells 5 times shorter than broad; I, 12// 

 broad, cells 3 times shorter than broad ; CI, cells 4 times shorter 

 than broad; M; W, 1.3*3-14-3/1 broad, 2-5-3/1 long; Cr ; SL, a 

 well-marked form, 9*5-] 1// broad, 6-8// long, apical cell subcapitate ; 

 W, 12// broad, 3 - 5// long. 



