new Forms of American Rotifera. 27 



relationship to Copeus, from which it is separated by the 

 smaller size, the more active movements, and especially by 

 the entire non-lobate brain. 



The stomach bears an internal undulating organ similar in 

 general appearance and in movement to the membranous 

 appendage within the stomach of Monostyla rohusta and of 

 certain other Rotifera. The animal has entire control over 

 the movements of this appendage, hastening or retarding 

 them, or throwing the membrane into various convolutions 

 and irregular vibrations. 



The wing-like extensions of the body apparently carry none 

 of the internal anatomy except the lateral canals, which are 

 almost entirely contained within a narrow elongate mass of 

 granular tissue, where there seems to be but one flame-cell, 

 and that usually indistinct. Other vibratile cells probably 

 exist, but they are not ordinarily visible. With many speci- 

 mens of the Hotiferon, which is not rare in my locality in 

 New Jersey, I have not been able to discover any other 

 arrangement than this of the vascular system. 



The tail is usually as shown in the figure (fig. 21), but 

 occasionally the bulbous portion is less distinct, while the 

 entire appendage seems to be somewhat elastic and changeable. 



EXPLANATION OF THE PLATES. 



Plate VIL 

 Fig. 1. Masti(/ocerca mucosa. 

 Fig. '2. Tuphrocampa davigera. 

 Fig. 3. Metopidia collaris. \'entral view. 

 Fig. 4. Ditto. Front of dorsum. 

 Fig. 5. Metopidia collaris, var. similis. Lorica. 

 Fig. 6. Monostyla hamata. Dorsal view. 

 Fig. 7. Ditto. Ventral view. 

 Fig. 8. Ditto. Expanded front. 

 Fig. 9. Monostyla rohusta. 

 Fig. 10. Ditto. Malformed toe. 



Plate VIII. 



Fig. 11. Monostyla bipes. Lateral view. 



Fig. 12. Ditto. Dorsal view. 



Fig. 13. Ditto. Ventral front. 



Fig. 14. Salpina similis. Front of lorica. 



Fig. 15. Ditto. Side view of animal. 



Fig. 16. Ditto. Dorsal view of animal. 



Fig. 17. Ditto. Posterior extremity of small variety. 



Fig. 18. Ditto. Lorica front of small variety. 



Fig. 19. Mattuhts palpitatus. Lateral view. 



Fig. 20. Notommata viirabilis. 



Fig. 21. Ditto. Tail. 



