B ATRAC HOSPERMEvE. 
61 
This genus scarcely differs from Ulva on the one side and Palmella on the other. 
The frond is more gelatinous that in Ulva ; and more membranous than in Palmella. 
The whole of the endochrome is converted into spores, which are arranged in squares 
and more distantly placed than in Ulva. 
1. Tetraspora lacunosa i Chauv. ; frond at first tubular, then flat, or irregularly 
lobed, membranaceo-gelatinous, pale -green, everywhere pierced with roundish holes of 
various sizes. Chauv. Alg. Norm. Breb. Alg. Fal. p. 11, t. 1. Kutz. Sp. Alg. p. 
227 . T. Godegi, De Breb. Kutz. Tab. Phyc. t. 30 ,/. 3 . T. perforata, Bailey , M.S. 
ITab. In fresh-water streams. Abundant near Westpoint, Prof. Bailey. Providence, 
Rhode Island, Mr. Olney. (v. s. in Herb. T.C.D.) 
Frond at first funnel-shaped, afterwards splitting open, and then flat, expanding 
upwards and irregularly lobed, everywhere pierced with roundish holes of various sizes, 
large and small intermixed. These holes increase in size and numbers with age, and 
thus at last the frond becomes an open network. The substance is very gelatinous, but 
rather firmer than in some other species of the genus. The colour is a pale green ; and 
the hyaline gelatinous membrane is filled with roundish granules set in fours. 
Kiitzing’s figure of T. Godeyi answers well to our plant. I have not seen any 
authentic specimens of T. lacunosa , which is referred by Kiitzing to his T. lubrica , 
var. 13., but the description given of it applies to the American plant. When carefully 
dried, it forms a very pretty object for the Herbarium. 
Order V. — BATRACHOSPERMEiE. 
BatrachospermetE, Ag. Syst. p. 23 , (partly) Harv. Man. Ed. 1 , p. 119 . Berk. 
Crypt. Bot. p. 136 , P>ne. class, p. 33 (partly .) Kutz. Sp. Alg. p. 535 . Lemanieoe, 
Ag. Sp. Alg. 2 , p. 1. Harv. Man. Ed. 1, p. 118 , Dne. Class, p. 31 . Kutz. Sp. 
Alg. p. 527 (partly .) 
Diagnosis. Blackish-green, olivaceous or purplish fresh water Algae, with filiform, 
branching, inarticulate fronds, composed of small cells ; naked, or whorled with monili- 
form ramelli. Fructification ; moniliform strings of naked spores, either forming 
external tufts, or concealed within a tubular frond. 
Natural Character. Boot merely a point of attachment or little disc, by which the 
frond is firmly fixed to the substances (usually rocks and stones in -rapid rivers and 
