MICROSCOPICAL MEMORANDA. 95 



to give rise to the supposition of an animal nature, even when they are 

 called infusorial or animal motions. Internal nutritive organs, and a 

 definite oval aperture for the reception of solid substances, which may 

 be demonstrated, distinguish the apparently most simple animal from 

 plants. Ehrenberg has never seen, in his numerous experiments, the 

 motive Algse seeds take up the smallest quantity of solid nutriment ; 

 and thus the fruit strewing Alga may be distinguished from the Monades 

 which swarm round it in the same manner, as the tree from the bird. 

 Ehrenberg in Poggendorff's Annalen. Taylor s Sclent. Mem. Vol. I. 

 p. 566. 



Gulliver on the Ova of the Distoma Hepaticum. The physiology of 

 the common Liver Fluke is extremely interesting, on account of the 

 connection which this parasite has with a very frequent and fatal dis- 

 ease of that useful animal, the sheep. " If we obtain," says Mr. G., 

 " from the bile-ducts of the sheep, some of the larger ova of the Ento- 

 zoon, and subject them to careful examination, it will be found that the 

 cyst of the ovum presents a very clear outline, the continuity of which 

 is uninterrupted, except at one end, where a well-marked operculum 

 may be seen. The size of these ova differs considerably ; their average 

 length is about -^th of an inch, and their breadth 4^th. The inte- 

 rior of the cyst is occupied by granular matter, often contained within 

 secondary and more delicate cysts or cellules, generally of a circular 

 figure, and occasionally having within them a third still smaller cyst. 

 The diameter of the latter is about 4-^00*11 of an inch, and of the secon- 

 dary cysts TsVoth of an inch is a common size, although their magni- 

 tude is very variable. The granules within the cells or cysts also differ 

 much in size, but they are very commonly about g^oth of an inch in 

 diameter. When the ova of the Distoma are compressed forcibly, the 

 operculum is lifted up or even separated entirely, and the granular 

 matter extruded, with its containing cells or cysts generally broken. 

 The operculum does not appear to exist in the smaller and immature 

 ova. Whether what is commonly called the ovum of the Entozoon, may 

 may not be a cyst containing numerous ova within it, and furnished 

 with an operculum, to allow of their extrusion when mature, and fit 

 for propagation, appears to Mr. G. to be an interesting question. At 

 all events, it should be ascertained if the cysts be discharged with the 

 dung of the diseased sheep, whether the granules have escaped or not ; 

 and whether they are to be found in the pasturage of those localities, 

 where the Entozoon is sometimes known to be propagated so quickly 

 as soon to infect entire flocks of sheep. Mr. G. could never see any 

 thing like a small fluke in the outer cyst, at any period of its growth, 

 although the operculum was often observed just ready to open and give 

 exit to its contents, as above described. The granules may possibly be 

 regarded as yolk- globules, in which case Mr. G. apprehends the nume- 

 rous secondary cysts, or cells, must be considered as so many different 

 yolks." Proc. Zool.Soc. Lond., March 10th, 1840. 



Broderip and Brewster on the Structure and Optical Characters of 

 Bulinus velatus, and other Land- Shells, collected by Mr. Cuming. In a 



