160 Miscellaneous. 



Notice of some FresJnvatcr a)ul Terrestrial Rhizopodt. 

 By Tkok. Lkiuy. 



Prof. Leidy stated that among tho ama3boid forms noticed by him 

 in tho vicinity of rhiliidelpliia, there was one especially reniaikahle 

 for tho comparatively enormous quantity of (juartzose sand which it 

 6walli)wed with its food. The animal might be viewed as a ba-j; 

 of sand ! It is a slugjjish creature, and when at rest appears as 

 an opaquo white, spherical ball, raiij^ing from f^ to ^ oi a lino in 

 diameter. The animal moves slowly, first assuming an oval and 

 then a clavate form. In the oval form ono measured ^ of a line 

 long by ^ of a lino broad ; and when it became clavate it was | of 

 a lino long by ^ of a lino broad at the advanced thick end. Another, 

 in the clavato form, measured i of a line long by g of a line wide 

 at tho thick end. The creature rolls or extends in advance, while 

 it contracts behind. Unless under pressure, it puts forth no pseudo- 

 pods ; and the granular entosarc usually follows closely on tho limits 

 of the extending ectosarc. Generally tho animal drags after it a 

 quantity of adherent dirt attached to a papillated or villous discoid 

 projection of the body. 



The contents of tho animal, besides the granular matter and 

 many globules of tho entosarc, consist of diatoms, desmids, and 

 confervie, together with a larger proportion of angular particles of 

 transparent and mostly colourless quartz. Treated with strong 

 mineral acids, so as to destroy all the soft parts, the animal leaves 

 behind more than half its bulk of quartzose sand. 



The species may be named Amoeba sabulosa, and is probably 

 a member of the genus Pelomyxa of Dr. Greef (Archiv f. mikr. 

 Anat. X. 1873, p. 51). 



The animal was first found on the muddy bottom of a pond in 

 Dr. George Smith's place in Upper Darby, Delaware County, but 

 has been found also in ponds in New Jersey. 



When tho animal was first noticed with its multitude of sand 

 particles, it suggested the probability that it might pertain to a 

 stage of life of Difflugia, and that by the fixation of the quartz 

 particles in the exterior, the case of the latter would be formed. 

 This is cV>njectural, and not confirmed by any observation. 



A minute amoeboid animal found on Spirogyra in a ditch at 

 Coopers Point, opposite Philadelphia, is of interesting character. 

 The body is hemispherical, yellowish, and consists of a grainilar 

 entosarc with a number of scattered and well-defined globules, 

 besides a large contractile vesicle. From the body there extends 

 a broad zone, which is colourless, and so exceedingly delicate that 

 it requires a power of 600 diameters to see it favourably. By this 

 zone the animal glides over tho surface. Delicate as it is, it evi- 

 dently possesses a regular structure, though it was not resolved 

 under the best powers of the microscope. Tho structure probably 

 consists of globular granules of uniform size, alternating with one 

 another, so that the disk at times appears crossed by delicate lines, 

 and at others as if finely and regularly punctated. The body of 



