276 FRESH- WATER RHIZOPODS OF NORTH AMERICA. 



able in shape, and without visible trace of the latticed capsule of the mature 

 animal. The body was composed of granular protoplasm, with numerous 

 oil molecules and vacuoles. From time to time a deeper one of the latter 

 would slowly approach the surface and project above its level, but, would 

 remain a long time unchanged. Occasionally one of the superficial vacu- 

 oles would slowly and feebly contract and disappear, but, none presented 

 otherwise the aspect, of the contractile vesicle of Actinophrys sol. A nucleus 

 was indicated by a clearer central spot. The pseudopodal rays were like 

 those of Actinophrys sol, but from time to time one or two would become 

 thicker, and occasionally a considerable vacuole would form on one or more 

 of them. 



The thickened stem of this individual was attached by radiating threads, 

 or perhaps these may have been delicate folds of an exceedingly delicate 

 membranous disk. 



Most frequently the individuals of Clathrulina I have seen happened 

 to be such as were in an encysted condition, as represented in figs. 6-9. 

 In these the latticed capsules, colored and colorless, contained one or two 

 large spheres, which were colorless and granular, with scattered oil molecules 

 and a central nucleus. They occasionally presented a few larger globules or 

 vacuoles, as seen in fig. 6, and were always devoid of pseudopodal rays. 



From the observations of Cienkowski, on the mode of reproduction of 

 Clathrulina, it multiplies by division. According to him, the Actinophrys- 

 like body within the latticed capsule undergoes constriction and divides into 

 two. After a time the pair of animals withdraw their pseudopodal rays, 

 and then appear as simple granular spheres. These pass out of the latticed 

 capsule, and assume the appearance of the common Sun-animalcule, which 

 subsequently develops a stem of attachment, and finally a latticed capsule 

 enveloping the sarcode head. Sometimes the original Actinophrys-like 

 body divides into four, and at times assumes the smooth spherical form 

 without division. 



The different examples of Clathrulina elegans represented in pi. XLIV 

 would appear to exemplify nearly all the stages of development, including 

 those of maturity. 



