190 



THE AMERICAN MONTHLY 



[October, 



anterior part of the cavity of the 

 lorica, apparently not attached to the 

 walls ; endoplasm granular ; tentacles 

 fasciculate, all the distinctly capitate 

 extremities usually placed on the 

 same side of the fascicle, each of 

 which consists of about six tentacles ; 

 nucleus ovate, subcentral ; contractile 

 vesicle single, spherical, posteriorly 

 situated near the lateral border. 

 Length of lorica, with pedicel, -^\ 

 inch ; of the enclosed zooid g^ inch. 

 Habitat. — Fresh water, on Cerato- 

 phylluni. 



A single individual of this curious 

 and beautiful acineta was first obser- 

 ved about three years ago ; none have 

 since been seen until recently, when 

 they were obtained in some abun- 

 dance. The projecting wing-like ad- 

 ditions are \txy strongly flattened, 

 the margins usually being undulate 

 or irregularly crenate. It is difficult 

 to rotate the lorica on its long axis 

 so as to obtain a view of all the pro- 

 jecting alae in succession, and to be 

 certain of the exact number, the ob- 

 server being forced to content him- 

 self with an examination of the oppo- 

 site surface through the entire thick- 

 ness of the semi-transparent animal- 

 cule. The usual number seems to be 

 five ; it varies, however. I have not 

 succeeded in obtaining an end view ; 

 figure 14, showing a horizontal optic 

 section of the lorica, is therefore not 

 only diagrammatic, but to a certain 

 extent ideal. The tentacles rarely 

 exhibit an external spiral film. 

 o 



The Pseudocydosis in AiiioBba. 



BY G. C. WALLICH, M. D., 



Surgi'on- Major Rei'd List, H. M. Indian Army 



In the March (1885) number of 

 your valuable journal. Dr. S. Lock- 

 wood draws attention to the fallacy 

 of the view still prevalent amongst 

 naturalists in relation to the charac- 

 teristic movements of granular and 

 other particles within the body-sub- 

 stance of Afnccba; and he furnishes 

 the only rational explanation of the 

 phenomena which is compatible with 

 the readily observable facts of the 



case. The title of Dr. Lockwood's 

 brief but highly interesting paper, 

 coupled with the arguments he brings 

 forward, at once establishes his rejec- 

 tion of the idea that the movements 

 of the particles referred to are indica- 

 tive of the existence of a special cir- 

 culatory function in the protoplasmic 

 structure of this organism. 



Having published, in The Annals 

 and Alagazine of Nattiral History ^* 

 upwards of thirty years ago, a series 

 of articles on the Amceban and Dif- 

 flugian Rhizopods, in the course of 

 which the quasi-circulatory move- 

 ment of particles i n the body- substance 

 o{ Amoeba was fully explained on pre- 

 cisely the same basis as that recently 

 advanced by Dr. Lockwood (the 

 term pseudocydosis having then been 

 assigned by me to the phenomenon, 

 as will be presently shown) , I venture 

 to hope you will give the present com- 

 munication a place in your columns. 

 I w^ould, however, at once assure Dr. 

 Lockwood that I feel perfectly confi- 

 dent his conclusions on the subject 

 have been arrived at quite independ- 

 ently of mine ; and that it is a 

 source of great satisfaction to me to 

 find my own views have been thus 

 verified by so painstaking an ob- 

 server. 



The following extracts fi'om my 

 papers, which could be multiplied 

 were it necessary, will doubtless suf- 

 fice to prove my statement : — 



' Another fact is deducible from the 

 appearances presented by the sar- 

 code-substance of the largest of these 

 Amceba. The rush of granules does 

 not follow upon a previous contrac- 

 tile effort exercised at the posterior 

 portion. As the animal pi'ogresses, 

 occasionally altering its course, there 

 are periods during which perfect 

 quiescence is maintained b}' the gran- 

 ules ; and the rush or flow of these 

 seems to take place, as it were, to fill 

 up the vacuum engendered by the 

 sudden projection of a portion of the 

 ectosarc in the shape of a pscudopo- 

 dium. Hence it would appear that 



* London : Taylor & Francis. 



