ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 973 



development, being found as a zoospore, an amoeba, and also in a resting 



state. 



Tbe zoospore is a spberical body, and possesses a cilium 1^ to 2| 

 times its lengtb. It contains 1 to 2 contractile vacuoles, numerous drops 

 of oil, and a nucleus whicb is only demonstrable after fixation with 

 picric acid, washing with spirit and water, and staining, say, with gentian 

 violet. Tbe transition stage to tbe amoeboid form is shown by the 

 gradual diminution and finally the cessation of movement of the 

 flagellum. 



Amoeboid stage. In this condition tbe animal is less spberical. 

 Tbere are no true pseudopodia, but merely coarse projections. The 

 nucleus is only visible after staining with gentian-violet and previous 

 fixation. Tbe amoeba measures 6 to 9 /a in length, and 6 to 8 /x_ in 

 breadth, is inclosed by a delicate investing membrane, and contains, like 

 tbe zoospore, numerous small drops of oil. These last gradually coalesce 

 to a single large drop situated excentrically. Tbis forms the transition 

 stage to the resting condition. 



In tbe resting stage tbe investing membrane tbickens, and sbows a 

 double contour, while in its general appearance its surface seems covered 

 with curved facets. Tbis membrane does not stain blue witb the 

 cblor-zinc iodine solution, tbus sbowing tbe absence of cellulose. It is 

 coloured red with congo. The spores contain, besides the oil-globules, 

 small slightly refracting spherules. These are not stained by osmic 

 acid, but are by congo red. The author has called his organism Endo- 

 biella, and regards it as a new genus. 



Monas Dunali.* — Dr. R. Blanchard has a preliminary notice on 

 Monas Dunali, a flagellate which he regards as the cause of the red 

 colour of salt marshes. This red colour appears in summer, but only in 

 the rectangular coaipartments at the bottom of which salt is deposited, 

 and the surface of which is covered by a more or less thick crust of salt ; 

 in other words, the water of these spaces is saturated with salt. 



Asellicola digitata.| — Dr. L. Plate has given the name of Asellicola 

 digitata to tbe " gefingerte Acinete " of Stein ; it lives on the branchial 

 plates of Asellus aquaticus. It is non-pedunculate and hemispherical, and 

 adheres closely to the surface of the gill-plate by its flattened but gently 

 rounded under surface. The thin cuticle is continued over the numerous 

 tentacles which radiate from the dorsal surface. The protoplasm is not 

 divisible into a central or a cortical layer, but is homogeneous throughout. 

 Tbe contractile vacuole, as in Dendrocometes paradoxus, opens directly 

 outwards by a small duct, and contracts in such a way that the fluid 

 which has collected in it must be pressed out through tbis tubule. The 

 striated appearance presented by the protoplasm is not in any way 

 connected with tbe sucking organs, but has probably only the function 

 of giving the cell-body an increased degree of firmness at its point of 

 fixation, by the development of rigid rods. 



The tentacles are remarkably broad, end acutely, vary in number in 

 different individuals, and may arise from any part of tbe dorsal surface ; 

 the plasma is quite free from coarse granules, and in the middle there is 

 a longitudinal canal filled with a limpid fluid, which opens at the 



* Bull. Soc. ZooL France, xiii. (1888) pp. 153-4. 



t Aun. and Mag. Nat. Hist., ii. (1888) pp. 208-19 (7 figs.). Translated from 

 Zocl. Jalirb. (Speugel), iii. (1888^ pp. 143-55. 



1888. 3 u 



