78 PROFESSOR O. BuTSCHLI. 



not been observed by the author, although he does not doubt 

 but that it is present. 



The process of reproduction has not been followed, but it 

 almost certainly increases by fission, like its fellows. In the 

 formation of a colony one of the young buds, as in the case 

 of Dinobryon, settles upon the rim of the old calyx, and 

 builds there a new case for itself; and in this way from a 

 single one arise the compound trees of a great number of indi- 

 viduals. Clark has found a second variety of this species, 

 Bicosceca gracilis ; it is a marine form. 



The Stylobryon insignis of Fromentel^ forms definitely a 

 third kind, which differs chiefly from Bicosceca lacustris in 

 the fact that each calyx of the colony possesses its own very 

 long stem ; this form stands somewhat in the same relation 

 to Bicosceca lacustris as Dinohryon petiolatum Duj. to the 

 ordinary Binohryon sertularia. 



Dinobryon, Ehrbg ('Die Infusionsthiere als vollkom- 

 mene organismen,' Leipzig, 1838, p. 124). 



Dinobryon setularia, Ehrenberg (op. cit., p. 124, pi. 



vii, fig. 8). 



Dinobryon, Dujardin (' HistoireNat. des infusoires,' Paris, 

 1841, p. 321, pi. i, fig. 2). 



Dinobryon^ Perty (' Zur Kenntniss kleinster Lebens- 

 formennach Bau, Function, Systematik,' &c., p. 178). 



Binohryon, Claparede and Lachmann ('Etudes sur les 

 Infusoires,' p. 65, pi. xii, fig. 66)^^ 



Binohry on, YxomQwi^X E. de (' Etudes sur les Microzoaires,' 

 Paris, p. 336, pi. xxvi, fig. 1). 



Of this beautiful form Biitschli states that he has found 

 only free swimming colonies (Plate vi, fig. 13). The 

 vase-like case of the individual organisms calls to mind 

 the very similar cases in Bicosceca and Salpingoeca, whilst 

 the grouping of the individuals to form a colony is just like 

 the arrangement in Bicosceca lacustris. The young calyces 

 also grow from the inner side of the free edges of the old 

 forms, generally single but occasionally double. The or- 

 ganisms are of a yellowish-brown or green colour, the colours 

 proceeding, as in many coloured Flagellata, from two pigment 

 discs, which are placed side by side on the colourless proto- 

 plasm of the body (fig. 13 a and 13 b). Of these discs one is 

 generally the longer, and extends further forward than the 

 other. Ehrenberg noticed thatthe smallinhabitantsof thecases 

 were very contractile ; from the anterior end springs a rather 



' Op. cit., p. 336, pi. ix, figs. 12—14 ; pi. xxvi, fig. 8. 



