GENUS DINAMCEBA— DIKAMCEBA MIEABILIS. 81 



ally furcate. Posterior extremity of the body papillose; papillae very 

 variable, few or many, simple or compound, retractile. Surface of the 

 body, including the pseudopods and the papillae, bristling with minute 

 spicules or motionless cils.* Body of the animal often enveloped, even in 

 the active moving condition, with a thick layer of delicate hyaline jelly, 

 defined on the surface by multitudes of minute spicules. Spicules of the 

 surface of the body and the exterior layer of jelly with its spicules some- 

 times absent. 



DINAMCEBA MIRABILIS. 



Plate VI; VII, figs. 1-11. 



Deinamceba miraUUs. Leidy : Pr. Ac. Nat. Sc. 1874, 142, 155. 

 Amoeba ientaculata. Leidy : Pr. Ac. Nat. Sc. 1874, 167. 

 Dinamoela. Leidy: Pr. Ac. Nat. Sc. 1877,288. 



Body round, oval, ovate or limaciform,t commonly more or less 

 depressed when moving on flat surfaces ; anterior part broad and blunt ; 

 posterior part narrower and more or less tapering: sometimes broader 

 behind; spheroidal when floating. Pseudopods mostly numerous, and 

 usually projecting from the anterior region of the bod}^, consisting of 

 moderately long, conical, or somewhat fusiform, or subulate processes of 

 clear ectosarc. Posterior extremity of the body commonly much papillose, 

 with the papillae very variable, simple or compound, rounded or elongated. 

 Surface of the body everywhere, including pseudopods and papillae, thickly 

 bristling with minute spicules, which are, however, in some conditions 

 entirely absent. Body often enveloped with a thick layer of clear proto- 

 plasm, which is defined by a minutely ciliated surface, and is penetrated by 

 the pseudopods. Endosarc mostly v/ith abundance of oil-like molecules, 

 large clear globules, and multitudes of food-balls. Nucleus and contractile 

 vesicles commonly obscured from view by the other constituents. 



Sise. — Spheroidal form 0.064 to 0.16 mm. diameter. Creeping forms 

 152 mm. long by 0.06 mm. broad, to 0.34 mm. long by 0.22 mm. broad. 



Locality. — Ponds of the cedar and sphagnous swamps of New Jersey, 

 commonly among ,the desmids Didymoprium and Bambusina, which appear 

 to be its favorite food. 



DinamcBba mirabilis in its quiescent condition is globular or oval, 

 and often appears indisposed to move. It is a sluggish animal,, though much 



* From the word ' dlia, ' anglicized into ' dU ' — minute linear appendages, in rows reminding one of 

 the eyelash, whence the name. 



t Shaped like a Limax, or sing. 



6 BHIZ 



