11 



a certain determination was not possible. On the other hand, 

 as Pringsheimia scutata is found at Jamaica and most probably 

 widely distributed, it may also be expected to occur at other 

 places in the West Indies. 



The above mentioned specimens were found: 



St. Thomas: Store Nordside Biigt. 



Geogr. Distrib. Europe, Greenland, Atlantic coast of North Ame- 

 rica, Jamaica, St. Thomas. 



2. Pringsheimia (?) Udoteae nov. spec. 

 Thallus viridis, disciformis, minutus, horizontalis, tota in- 

 feriori parte substrate adfixus; cellulis in media parte disci saepe 

 irregulariter dispositis ad 

 marginem versus radianti- 

 bus saepe etiam concen- 

 trice ordinatis. Discus 

 crescit divisione cellularum 

 peripherise. Zoosporangia 

 urceolata, poris rotund- 

 atis singulis instructa, in 

 parte superiori apertis. 



Growing epiphytic 



upon the flabellum of a 



specimen of Udotea flabel- 



lata were found numerous 



small roundish discs of a 



bright green colour. When 



examined under the micro- , „ ,, . j „ , ^, ,, „ , „ 



^, ,. „ a, part of the middle of the thallus; o, the 



scope these discs seen from edge of the thallus, c, edges of two thallus 

 above were found to be growing together; d, zoosporangia seen from 



, „ ,1,1 a bove; e, transverse section of thallus. 



composed ot mostly rather (a, about 75 : 1, &,«? and e, about 200:1, c, 150:1). 



long cells arranged most 



often in nice radiating series and also in concentric rings with 

 exception of the middle of the disc where the arrangement 

 was less regular (Fig. 3 a). The cells are commonly about 16 ^ 

 broad varying from 5 n — 25/-< and about 40 ;« long, the shortest 

 found being 17 // the longest reaching 70 fi. 



The disc increases by means of marginal growth (Fig. 3 6); 

 all the cells in the periphery are able to divide themselves. Some- 

 times only one cell is cut off by a cross wall, but most often two 



Fig. 3. Pringsheimia (?) Udotece nov. spec. 



