26 



that might not be attributed to their wonderfully rapid growth, which mufl 

 occafion fuch thickly entangled filaments to prefs againft each other ; to the 

 water in which they are examined, the flighteft motion of which is fufficient to 

 agitate them, or to the numerous animalculse with which they are constantly 

 ihf feed. 



It would exceed the limits of my prefent undertaking to give a detail of M. 

 Vaucher's numerous conjectures, and curious remarks, and I fhall therefore 

 now confine myfelf to the relation of what I have myfelf obferved concerning 

 this family. 



The Ofcillatoria constitute a natural genus, and are diftinguifhable at firft 

 fight by their numerous filaments fo thickly matted together as to form a jelly- 

 like mafs. The filaments, when examined w.th the higher powers of a micro- 

 fcope, appear to me equally obtufe at both ends, and are regularly divided by 

 remarkably delicate diffepiments into extremely fhort joints. Some of the dif- 

 fepiments may be obferved of a darker color and thicker fubftance than the 

 others, and at thefe I believe the filaments divide into feparate fragments, each 

 of which, as M. Adanfon firft obferved, " Devient abfolument femblable a 

 celui dont il s'etoit feparee, et capable d'en produire a fon tour de nouveau." 

 In C. vagirmta, however, the filaments are multiplied by a longitudinal inftead 

 of a tranfverfe divifion, as appears in my defcription of that fpecies. The 

 diameter of the filaments of this family, never varies according to their age, as 

 in other Conferva;, but is conftantly the fame in every fpecies, and hence M . 

 Vaucher has been led to fuppofe that they arc always propagated by the vivipa- 

 rous divifion only, and never by feed. This opinion I was for fome time inclined 

 to adopt, till it was fhaken by an appearance of capfules on fome fpecimens of 

 C. decortlcans, which is reprefented in my fupplementary plate. They are fo 

 unufually large in proportion to the thicknefs of the filament, that at firft fight 

 I thought they were of the fame nature with galls, or thofe excrefcences that 

 are fo frequently inhabited by the Cycl ps on the Vaucher'te, but, when I applied 

 the higheft powers of my microfcope, I found their fhape too regular and well 



