160 
Transactions of the Society. 
fusiformes, angulis subinflexis et subcapitatis cum spina singula 
valicla inflexa subcurvata, dorso spinis geminatis brevibus 
curvatis circiter 6 ornato ; a vertice visse triangulares, angulis 
obtusis et subcapitatis, lateribus leviter concavis cum spinis 
geminatis circiter 6 ad latus unumquodque ; membrana 
glabra. 
Long. s. spin. 20 /x, c. spin. 25 /x ; lat. s. spin. 23-26 /x, 
c. spin. 29-34 /x ; lat. isthm. 8 /x. 
Hah. Glen Caragh, Co. Kerry, Ireland. 
34. S. margaritaceum Menegh. (Synops. Desm., p. 227 : Kalis, 
Brit. Desm., p. 134, t. xxi. f. 9). PI. IV. fig. 36. 
Zygosporse globosae, spinis obsessae, apicibus spinarum 
dichotome furcatis. 
Diam. zygosp. sine spin. 31 /x, c. spin. 52 /x. 
Hob. Devil’s Jumps, Frensham Common, Surrey. 
ClaSS CcENOBIEJE. 
Order Pandorine#}. 
Tetragonium g. n. 
Coenobium e cellularum quattuor strato singulo horizontali piano 
formatum ; cellulis ovoideis subparallelis cruciatim ordinatis, con- 
tentum chlorophyllosum cellularum laete viride granulosum, polo 
angustiore acbroo, et cum ciliis binis perlongis instructs; cellulis 
processibus latis brevissimis (cum uno cellulae unaquaeque) connexis. 
Propagatio formatione cellularum filialium quattuor in cellula matricali 
oritur. 
35. T. lacustre sp. n. PI. II. figs. 1-13. 
Character idem ac generis. 
Long. cell. 11 ‘5-19 /x ; lat. cell. 7 *5-15 *5 /x ; diam. 
coenob. 28-47*5 fi. 
Hah. In “ Black Lake,” Esher Common, Surrey, in pro- 
fusion amongst Sphagnum, Lancashire (Narramore). 
It appears to be very distinct from the only other allied genera, 
Gonium and Pandorina. Mr. W. Narramore * mentions a plant 
which we take to be this. 
The cilia of each pair form an angle of 30° to 40° with each other ; 
they are very long, and they appear to be actively vibratile only in 
their terminal portions ; for this reason the progression of the colony 
is comparatively slow. The cells are joined by a short colourless 
projection from each cell, which are seen best in the vertical view of a 
colony. This connection is very fragile, and the cells easily separate ; 
pairs of them may often be seen swimming about. The four cells 
are not quite parallel, but are divergent, with their narrower ends 
outwardly inclined. The colourless narrower ends of the cells in 
* ‘List of the Freshwater Algae of the Liverpool District,’ Trans. Bio. Soc. Liv., 
v. p. 284. 
