NOTES ON BRITISH DESMIDS. 
91 
Cosm. hiretum. By many features this seems to be entitled to rank 
as a distinct species. 
Cosmaxium cambxicum, Che. & Wills. 
Frond longer than broad ; constriction linear ; segments quadri- 
lateral, narrowed from the base, sides with two sinuations, and one 
in the centre of the end, the latter rather the broadest. Side view, 
segments oval, narrow, rounded at the ends, with a shallow con- 
striction. End view elliptical. 
Length, 'OdG-’OdS mm. Breadth at the base, ’OSG-’OSS mm., 
at the end, *02-*022 mm. 
Allied to C. tetragonum and C. Nymannianum, from both of which 
it differs in the character of the sides and ends, and the number of 
sinuations. It has been found in two or three stations in North 
Wales, but not elsewhere. The empty frond seems to be minutely 
punctate. 
Cosmaxium globosum, Buln. var. 
Empty frond, punctate, with a distinct border, the punctge in 
diagonal lines. End view circular. 
Length, -035 mm. Breadth, *022 mm. Breadth at constriction, 
•019 mm. 
Of the species of Staurastrum one of the most noteworthy is — 
Stauxastxum Bxasiliense, Nordst. 
A large and beautiful species, of which numerous specimens 
were found, quite new to the British Islands (PI. 140, figs, d, e). 
Stauxastxum axctiscon, Ehr. 
Not uncommon in the gathering, previously found in Ireland, 
but now for the first time in Britain. 
Stauxastxum ophiuxa, L^md. 
Uniformly with eight arms (PI. 140, figs, a, 5, c) only recorded 
hitherto in Connemara. 
Stauxastxum cexastes, Lund. 
A most distinct species, which cannot be confounded with any 
other. Bare in the present gathering. Becorded by Mr. Archer 
in Ireland. 
Stauxcistxum avexsum, Lund. 
Similar in many respects to Staurastrum hrevispina^ Breb. Pre- 
viously recorded in Ireland (PI. 140, figs, q h). 
Stauxastxum gxande, Lund. 
A large species (PI. 140, fig. 4) not before in the British list. 
In the majority of the specimens there is a very minute papilla on 
each side of either segment, and consequently at the three angles 
of the end view. This form is not represented on the plate, indeed 
the minute papillae were not observed until after the plate was 
printed. 
Stauxastxum longispinum, Bailey. 
The form found and figured (PI. 140, fig. 9) is the same as that 
of Northern Europe, and not exactly that of the United States, It 
had already occurred in Ireland. 
