Miscellaneous. 263 



and endowed with alternate movements of contraction and expan- 

 sion. He has since succeeded in observing the contractions of the 

 spot in the living animal. Notwithstanding the analogy which these 

 phenomena present to those observed in the Infusoria and Rhizo- 

 poda, their signification remained obscure until the acquisition of a 

 better notion of the morphological condition of cells. Thus the 

 movements of the germinal spot could not be assimilated to those 

 of which the contractile vesicle of the animals just mentioned is the 

 seat, as in the ovules and other cells of animals we were unacquainted 

 with any canals comparable to those connected with the contractile 

 vesicle of the Infusoria. These the author now professes to have 

 discovered, from which he considers we are justified in assuming the 

 existence of a true circulation in these elementary parts of the 

 organism. 



The animal on the ovule of which the author's observations were 

 made is Geophilus longicomis. When the fresh ovary of this My- 

 riopod is placed under the microscope, and the ovules are examined 

 through its walls, an organ is detected which possesses more bril- 

 liancy than the surrounding vitellus, and appears like a prolon- 

 gation of the germinal vesicle. "With slightly acidulated water this 

 appears distinctly as an infundibuliform canal, more or less recurved, 

 of which the wider orifice is continuous with the membrane of the 

 vesicle, whilst the opposite extremity reaches the surface of the 

 vitellus. Generally the canal seems to terminate suddenly at this 

 point, opening by a circular orifice under the envelope of the ovule ; 

 but sometimes it appears to be continued into a delicate prolonga- 

 tion, emitting ramifications which spread more or less over the sur- 

 face of the vitellus. In certain positions the axis of the canal is 

 seen to be occupied by a much narrower interior canal, proceeding 

 from the germinal spot and narrowing rapidly after penetrating 

 into the outer canal. 



The germinal spot is occupied by a greater or less number of va- 

 cuoles, capable of alternate contraction and expansion. At the 

 moment of the extreme expansion of one of these vacuoles its walls 

 appear to be directly continuous with those of the canal which ter- 

 minates at the spot, the vacuole then looking like the enlarged am- 

 puUiform end of the latter. When less dilated and seen in profile, it 

 appears only to communicate with the canal by a narrow aperture , 

 like a pore. 



The width and apparent length of the two canals are in relation 

 to the degree of development of the ovules ; but they are to be seen 

 in the youngest. In older ovules they continue visible as long as 

 their transparency is not obscured by vitelline elements ; and they 

 probably persist as long as the germinal vesicle and spot. 



In seeking for similar structures in other ovules, the author ar- 

 rived at the following results : — In the ovules of the Bitch the vesicle 

 and spot each present a canal, as in Geophilus. In the Skate, the 

 ovules of which usually contain from one to four small germinal cor- 

 puscles with a central vacuole, each of these emits a variable number 



