174 ANNALS OF SCOTTISH NATURAL HISTORY 



13. M. radiosa, . Ag. Extremely rare. Aberdeen Slewdrum, 



Aboyne, and Birsemore Lochs. 



P ornata, Nordst. Extremely rare. Inverness near 

 Brin; Aberdeen Slewdrum, and near Craigendinnie 

 Farm ; Kincardine Scolty Dam. 



14. M. rotata (Grev.), Ralfs. General. Conjugated examples with 



zygospores have been found in Aberdeen at Slewdrum, in 

 Kincardine between Bishop's Dam and Clochnaben, and in 

 Forfar on Monroman Moor. 



1 5. M. Thomasiana, Archer. Not very common. Ross, Aberdeen, 



Kincardine, Forfar, Perth, Stirling, Dumbarton. 



1 6. M. truiicata, Corda. General and abundant. A variable species, 



of which several forms have been observed. One found in 

 Glen Dye, in Kincardine, strongly suggested Nordstedt's M. 

 adscendens. Unfortunately only one example was seen, 

 several years ago. 



i "j.**M. verrucosa, Bisset. Rare. Figured and partially described by 

 Wolle in the " Bulletin of the Torrey Botanical Club," pp. 

 127-128, Tab. II. fig. 10, December 1885. 



Large, about one-fifth part longer than broad, with num- 

 erous lobed or subgranulated prominences scattered over its 

 surface, of which three at the base of the semi-cell close to 

 the isthmus are larger than the others, and distinctly lobed ; 

 usually there are four on each side of these, reaching close to 

 the margin these are smaller, and sometimes indistinct; there 

 are usually about eighteen others, four on the end lobe, five 

 on the upper side lobes, and two on each of the basal lobes, 

 but these numbers are liable to vary ; the margin of the 

 end lobe and upper side lobes resembles $f- angulosa, 

 Hantz., while the margin of the basal lobes is nearer M. 

 denficulata, Breb. ; the end view, owing to the numerous 

 prominences, is very irregular. Cell very thin; membrane 

 brownish. 



This very interesting species is related to M. angulosa, 

 Hantz., in much the same way as M. denticulata, Breb., is to 

 M. Thomasiana, Archer. It is not granulated in the ordinary 

 sense; the prominences seem flattened, and their margins 

 cut into rounded segments, similar to the stigma of a species 

 of Poppy, only more deeply cut. Length, 2 1 o /z ; breadth, 

 i8o/-i; isthmus, 29/z (Plate IV. fig. 2). Aberdeen Collie- 

 ston, Bennachie, Powlair in Birse (where it was detected by 

 Mr. Bisset in 1877), Slewdrum, "Old Road" Aboyne, beside 

 Birsemore Loch, Moss of Logic, Morven, Dalbagie ; Kincar- 

 dine Crathes, pool north-west side of Kerloch. 



