672 PROCEEDINGS OF THE ACADEMY OF [Sept.. 



Length of lorica, the equivalent of 50 il 



This is one of the largest of the genus, and one of the rarest in Dela- 

 ware Valley. The writer has seen at most three specimens, and in one 

 of these the lorica was colored a deep brown. 



Trachelomonas armata (Ehr.) Stein. PI. XLI, figs. 9, 10 and 11. 



ChoEtolyphla armata Ehrenberg. 183.3. Abh. Berlin. Akad. 

 Choetotyplila aspera Ehrenberg. 1833. Abh. Berlin. Akad. 

 Trachelomonas armata Stein. 1878. Infnsion.sthiere, III. 

 Trachelomorias acanthostoma Stokes. 1887. Proc. Amer. Pliilos. Soc. 



"C. armata. C. corpore ovato, utrinque rotundato, subgloboso, 

 fusco, ubique setis brevibus hispido, corona apiculorum postica, nigra. 



"C. aspera. C. corpore oblongo, fusco, utrinque rotundato, ubique 

 setis brevibus hispido, apiculus posticis minoribus sine ordino sparsis." 

 — Ehrenberg, Ahh. Berlin. Akad., 1833. 



Lorica ellipsoidal, brown, the general surface deasely and finely 

 punctate. Two irregular rows of short, conical spines around apertm'c. 

 Often a ring of six to twelve or more long, hollow, curving spines 

 around posterior end. Aperture in a shallow, wide, rimmed depression, 

 and infrequently produced into a short tube with stellate limb. Length 

 of lorica 39 ;j-. 



This species is common in Delaware Valley and it exhibits much 

 variety of form. But among the thoasands of specimens examined, 

 not one has shown a lorica with the smooth surface attributed to the 

 species by authors. Dr. A. C. Stokes has accurately described his 

 form acanthostoma as having a punctate surface. This would unques- 

 tionably be a specific distinction were it not true that all forms of T. 

 armata, as found in this region, have precisely the same punctation. 



The posterior ring of large, curving spines seems to be a very lato 

 excrescence in the individual development, and these spines may be 

 seen in all stages of sprouting. 



Trachelomonas crebea Kellicott. PL XLI, fig. 1. 



Trachelomonas crebea Kellicott. 1887. Proc. Amer. Soc. Micros. 



" Lorica spheroidal, varying from decided brown to colorless, ellipti- 

 cal in side view, length to breadth as 5 to 4; surface not spined, but 

 with minute raised points over entire surface. Anterior projection 

 hyaline, minutely notched and slightly everted at outer extremit}'. 

 |- length of shell." 



The length of lorica is given by Kellicott at the equivalent of 25 p. . 

 This species, as it occurs along the Delaware, where it is not uncommon, 

 presents some variations. A prevalent form, figured herewith, is 

 indefinitely and coarsely punctate, the puncta? being of various sizes 



