480 On the Germination of the Spore in the Conjugata?!. 



XXXIX. — On the Germination of the Spore in the Conjugatse. 

 By the Rev. William Smith, F.L.S. 



To the Editors of the Annals of Natural History. 



Gentlemen, Lewes, November 10, ] 851 . 



Permit tne briefly to record a circumstance of much interest 

 as regards the germination of the reproductive body in the 

 family of the Conjugate, and which may serve to vindicate the 

 fidehty and discrimination of an eminent pioneer in the study of 

 algology. 



In examining the mud from a ditch in this neighbourhood, 

 hoping to add to my list of local Diatomacea, I had the pleasure 

 a few days since of discovering numerous " spores " of a Tyn- 

 daridea in every stage of gei"mination. This pha^nomcnon has 

 hitherto been seen by but few observers, but among these few 

 may be mentioned the honourable name of Vaucher; and so 

 faithful are his observations, made nearly half a century since 

 and with imperfect instruments, that his description will serve to 

 record the precise facts I have obsei'ved, with the exception of 

 the few words in italics, which are necessary to adapt his account 

 to the species which has fallen under my notice. I quote from 

 the passage as it is translated in the 'British Freshwater Algse,' 

 p. 22. 



^'Almost at the same instant and in the same day, or at least 

 in the same week, all the grains of the Tyndaridea cruciata, of 

 which I had many thousands, opened themselves by one of their 

 extremities in the same manner as the two cotyledons of a seed 

 whose embryo has become developed; and from the base of the 

 aperture there issued a green sac, at first very small, but which 

 soon extended itself in such a manner that it surpassed many 

 times the length of the globule. In the interior of this sac appear 

 soon the twin masses ofendochrome, as in a Tyndaridea fully deve- 

 loped. The tube itself exhibits divisions, at first one, afterwards 

 two, then a gi'cat number ; at last the Tyndaridea detaches itself 

 from its grain, and floats alone in the liquid, and then nearly in 

 size, and with two extremities, which are obtuse, it resembles 

 perfectly the plant which gave it birth.^' 



This passage is immediately followed in Mr. Hassall's work 

 by the followmg remark, upon which, with a multitude of speci- 

 mens exactly according with Vaucher's description before me, I 

 feel that it would be unnecessary to comment : — 



" In this description Vaucher is doubtless altogether in error, 

 and it is difficult to conceive in what way he could have been 

 imposed upon ; a careful microscopic examination of the ' spore' 



