1881.] 



MICROSCOPICAL JOURNAL. 



183 



ly burst through the cortex, and ap- 

 pear upon the surface of the thallus 

 in clusters, called Soredia ; or scat- 

 tered over it like green dust, when 

 the plant is said to be in a pulverulent 

 condition. 



The color of Lichens is very varied 

 and changing. This is greatly de- 

 pendent upon the place of growth, and 

 surrounding influences. There are 

 many shades of color, but few direct 

 and primary colors, — browns and 

 greys predominate. Green ranges 

 from dark olive to a pale greyish or 

 bluish-green. Yellow, from orange- 

 red and lemon to cream color and 

 white. Brown changes from pale into 

 chestnut and black ; and grey ranges 

 between white and black. These co- 

 lors are due to the gonidia, and the 

 contents of the cells of the cortex or 

 outer stratum of the thallus. 

 {^To be contimied.) 



Some Phenomena in the Conju- 

 gation of Actinophrys Sol.* 



BY J. D. COX. 



In the latter part of last winter the 

 opportunity occurred of making some 

 consecutive observations upon this 

 Rhizopod in an infusion in which it 

 appeared in considerable numbers, 

 and some of the phenomena are so 

 curious as to seem worthy of record. 



These phenomena more particu- 

 ularly relate to the conjugation of the 

 animalcule ; but before describing 

 them, I wish to note one or two 

 points, which have reference only to 

 the general form. 



Prof. Leidy, in his late work on 

 the Rhizopods, gives his opinion that 

 the rays of the Actinophrys are simply 

 gelatinous pseudopodia, of the same 

 substance as the body, and without 

 any solidified skeleton. The evi- 

 dence for this he finds in the bending 

 of the rays, under the force of a cur- 

 rent, like grass in a rivulet. I have 

 frequently observed this bending, but 



* Read before the Microscopical Section of 

 the A. A. A. S., at the Cincinnati meeting. 



when it occurs under the influence of 



a current in the water, or of a passing 

 animalcule of another kind, it has 

 been greatest near the tips of the 

 rays, and seemed consistent with a 

 more or less perfect solidity in the 

 parts near the spherical body. But, 

 what seemed conclusive, I have noted 

 instances in which, by the rush of a 

 Daphnia against the Actiiiophrys, the 

 greater mass and impetus of the crus- 

 tacean has broken the rays near their 

 base, leaving them at right angles to 

 their normal direction. 



Again, v/hen the Actinophrys passes 

 into a condition, which I shall refer 

 to a little further on, and which I 

 have described as the opaline, the 

 rays, in some instances, show a 

 marked appearance of being dis- 

 solved and not simply absorbed or 

 retracted. In some cases when the 

 animalcule suddenly collapsed, the 

 rays were left as granulated remains 

 of what they were, dissolving in the 

 water separate from the mass of the 

 body, much as if they were spicules 

 of crystal-sugar or some substance of 

 similar solubility. 



By this, I do not mean that the ray 

 was altogether of this character, for 

 the gelatinous covering was also made 

 manifest : first, by a rapid retraction, 

 or current, on its surface, by which 

 the more minute objects of its prey 

 were drawn toward the body of the 

 animalcule, and second, by a similar 

 outward motion by which the ejecta 

 were carried away from the body. 



When, in passing into the opaline 

 condition, the animalcule becomes 

 more transparent, a ring is seen near 

 its centre, which does not correspond 

 to the ordinary appearance of a nu- 

 cleus, as seen in the infusoria, but has 

 more the appearance of a small inner 

 sphere, such as is seen in the endo- 

 skeleton of some of the polycystinae, 

 and the rays appear to reach through 

 the sarcode of the outer body and to 

 connect with this. I will not speak of 

 this as proved, for the translucence 

 of the animalcule never becomes 

 transparence, and definite assertion 



