1902.] NATURAL SCIENCES OF PHILADELPHIA. 795 



were found in any of the five species, except in point of size as 

 already mentioned, and to a minor degree in perfection of develop- 

 ment, though not in character, of the surface markings. In par- 

 ticular, there seems to be no tendency toward intergradation in case 

 of any of those here described, or among the other very numerous 

 kinds, to be desci-ibed in a future communication, which accom- 

 pany them in this remarkable gathering. 



In addition to the numerous forms from A.ncora, N. J., others 

 equally silicious, but quite distinct specifically, have been detected 

 in small numbers among diatomaceous material from bogs and 

 ponds over a wide range of country. All these are being made 

 the subject of a careful study, the results of which are to be set 

 forth in a future paper. Unmounted fresh material, preserved in 

 formalin, which from its origin may be supposed to contain those 

 organisms, is greatly desired by the writer. 



EXPLANATION OF PLATE XXXY. 



The figures are drawn to a uniform scale, an enlargement of 

 1200 diameters. 



Fig. 1. — TracJielomonas tiestita n. sp. 



Fig. 2. — I'rachelomonas vestita optical median section. 



Fig. 3. — TracJielomonas vermiculosa n. sp. 



Fig. 4. — Trachelomonas spiculifera n. sp. 



Fig. 5. — TracJielomonas minor n. sp. 



Fig. 6. — TracJielomonas spinosa n. sp. 



