450 NOTES AND MEMORANDA. 



been nonrished by its contents, wliich had completely disappeared, 

 witb the exception of a few mucilaginous particles. 



8. An intracellular Floridea parasitic on the Thallus of a Por- 

 jjhjra. — On the margin of the thallus of Porphyra vulgaris (from 

 Marblehead, Massachusetts Bay) were seen minute reddish specks 

 formed by a peculiar parasite. Under a high power they were found 

 to consist of a single cell of singular form with a number of branches 

 radiating from its centre. The parasite had in these spots completely 

 consumed the tissue of the host. Most of the radiating branches of the 

 parasite were united in their growth with segmented bundles of cells 

 running through the thallus of the host, which are metamorphosed 

 cells of the Porphyra itself. The phenomenon presents the pecu- 

 liarity that the parasitic cell has taken up in its growth, not the 

 contents only but the cell-wall also of the infected cell. From this 

 the aiithor concludes, on physiological grounds, that the parasite 

 cannot be a fungus, but must be a Floridea nearly related to Porphyra 

 itself. 



9. Fungus-mycelium parasitic ivithin the Hen's Egg* — A hen's egg 

 of ordinary size, and presenting nothing abnormal in the structure of 

 the shell, skin, albumen, or yolk, showed, when held up to the light, 

 small bright dots on the shell ; the albumen and yolk were quite free 

 from foreign bodies, and the shell was without any fnngus-filaments, 

 and showed no perforations under the Microscope. The parasite con- 

 sisted of four hemispherical bodies with a diameter of from 4 to 4*5 

 mm., three of them of a greyish-brown colour, the other clear and 

 nearly transparent. They were composed of a densely interwoven 

 tissue of much-branched nearly transparent filaments, indistinguish- 

 fible from the mycelium which is ordinarily formed after a time in au 

 albuminous solution. The contents of the cell were quite clear, with 

 a few large colourless granules. The author suggests that the spores 

 must have entered the egg during its formation within the body of 

 the bird. 



10. Dactylococcus De Baryanus and floorer/.— These parasitic algfe 

 were first observed on small species of Copepoda (Cyclops and Lepi- 

 durus), where they occur in enormous quantities, appearing and again 

 disappearing with great rapidity, and giving them a distinct green 

 colour to the naked eye. The earliest condition of the parasite is that 

 of a tolerably large motile cell, with nmosba-like power of extension 

 and contraction, between 0-02 and 0*03 mm. in diameter. The con- 

 tents consist of green granules, among which is always one red one. 

 When stretched to its full length, one end of the cell is free from 

 granules, and at that end is a single rapidly vibratile cilium with club- 

 shaped apex. After a short time the cells lose their motility, and then 

 fix themselves to some part of one of the Entomostraca which are moving 

 about among them. The point of attachment of the parasitic cell 

 develops into a short clear pedicel, and the imion with the body of the 

 host becomes very close, and is effected with great rapidity. It does 

 not appear, however, to have any injurious effect upon the host. In 

 the female Cyclops hicaudatus the ovary in the last segment of the 



* See also this Journal, ii. (1870) 315. 



