ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 81 



present the form of long ribbons expanded at the ends and very 

 attenuated in the middle; their division results ultimately in the 

 production of an enormous number of small nuclei, distributed over 

 the external layer of the cyst at close and regular intervals. Soon 

 each of these nuclei recedes from the cyst, causing a projection from 

 its surface and drawing out with it a conical protoplasmic process; 

 this, inclosing the nucleus, becomes detached from the cyst by 

 constriction of its base, and constitutes a spore. 



Gregarinidse of Annelids.* — Professor J. Leidy describes and 

 figures four new species : Monocystis mitis in Distichopus (remarkable 

 from its frequently containing a variable number of curved elliptical 

 bodies — spores ?), Anoplophrya modesta and A. funiculus in the body- 

 cavity of Enchytrceus, and A. melo in that of a species of Lumhricus. 



Intestinal Parasites of the Oyster. t — In a further communica- 

 tion,J A. Certes describes the methods by which he obtained the con- 

 tents of the stomach of the oyster. A narrow tube is introduced 

 into the mouth of the animal, and the contents drawn out by suction ; 

 in this way the misleading presence of hepatic and generative cells is 

 completely avoided. Although the contents do not redden litmus 

 paper, the calcareous tests of Foraminifera are dissolved in the 

 stomach. The use of dahlia- violet, which colours living specimens 

 and slows their movements, has resulted in the demonstration of the 

 presence of a small oval nucleus. 



Attention is directed to the use of methyline blue, which the 

 author uses either to colour organisms already killed and fixed by 

 osmic acid, &c., or as a reagent for living protoplasm. In the latter 

 case, a drop of the alcoholic solution is placed on a slip, and allowed 

 almost to evaporate ; a drop of the liquid to be examined is then 

 added, and as soon as it begins to be coloured the solution is tipped 

 over, and the presence of crystals thereby avoided. 



By this means it is not necessary to add distilled water or alcohol, 

 which would immediately kill the organisms. 



There are some observations on Enchelyodon, but the author is not 

 yet satisfied as to the family to which it belongs ; and on Prorocen- 

 trum micans, in which a nucleus has been detected ; no observations 

 could be made on its supposed phosphorescence. 



Perception of Light and Colour by the lowest Organisms. § — 



The instances in which these faculties are exhibited in the lowest 

 forms, even extending to some true plants, are very numerous, but 

 hitherto have met with little explanation. T. W. Engelmann has now 

 turned his attention to the subject. The facts which he has dis- 

 covered, or with which he is acquainted, appear to him to point to 

 three principal modes by which light is able to affect these organisms, 

 viz. : — 



* Proc. Acad. Nat. Sci. Philad., 1882, pp. 146-8 (4 figs.), 

 t Bull. Soc Zool. France, vii. (1882) 7 pp. (1 pi.). 

 i See this Journal, ii. (1882) p. 804. 

 § Pfliiger's Arch. Physiol., xxix. (1882) pp. 387-400. 

 Ser. 2.— Vol. III. a 



