494 Miscellaneous. 



As regards the position of this group of obscure organisms, there 

 is naturally a great temptation to place it between true fungi and 

 Bacteria, though there is much to be urged against yielding to this. 



G. M. 



MISCELLANEOUS. 



On the Circulation of the Larva? of Ephemerae. 



By N. Cketttzbtjrg. 



In the microscopic investigations which I have made in the 

 laboratory of the Zoological Institution at Leipzig upon the circula- 

 tion of the blood in the larva? of Ephemera diptera, I have succeeded 

 in arriving at some interesting results, which I wish now to bring 

 into general knowledge as briefly as possible, reserving a more 

 detailed treatment of the subject to some future time. 



My observations, in which I availed myself of M. Verlooren s 

 memoir on the circulation of the blood in insects * as my foundation, 

 had for their principal object the part taken by the dorsal vessel in 

 the movement of the blood in the caudal seta? of the Ephemera-larva?. 

 This is effected, as indeed is shown by Verlooren in the above-men- 

 tioned memoir, by the contractions of a pyriform vessel, which, 

 situated in the last abdominal segment, appears to be a direct con- 

 tinuation of the dorsal vessel, and on a superficial examination may 

 easily be taken for its last chamber. This view is contradicted, 

 however, by the circumstance that this vessel is quite independent 

 of the contractions of the dorsal vessel. 



"With regard to this vessel Verlooren speaks as follows in the above 

 essay (pp. 84, 85) : — 



" We find in it no lateral apertures with their valvular arrange- 

 ment belonging to them, but in the middle a single apparatus, the 

 valvular membranes of which are opposite in direction to the valves 

 of the dorsal vessel. This apparatus therefore permits a flow of the 

 blood from bcfure backwards, a flow opposite to that occurring in 

 the dorsal vessel. 



" If this organ is connected with the posterior extremity of the 

 heart, it may be furnished by the action of the latter with blood, 

 which therefore will acquire a movement from before backward. 

 This blood will then be communicated to it by the heait-chamber 

 situated in the fourteenth segment. If no such union be present, 

 blood may be conveyed into it from without, from the body-cavity, 

 by the action of the valvular apparatus." 



The latter view appears to be regarded by Verlooren as in accord- 

 ance with the truth, for he says (p. 84) it seemed to him that no 

 communication existed between the heart and the vessel in question. 



* Mem, couronrt?.? de l'Acad. Roy, de Belgique, 4to, tome xix. 



