Protozoa and Rotifera <tt Havana, III. 371 



44. D. biraphis Gosse. 



This species was rare, being found only in bottom towings 

 from Quiver Lake in July. 



Famib RATTULIDiE. 



Mastigocerca Ehrbg. 



Body fusiform or irregularly thick, not lunate ; toe a single 

 long style, with accessory stylets at its base ; lorica often 

 furnished with one or more thin dorsal ridges. 



45. M. carinata Ehrbg. 



This form was not very common. It was mostly found, in 

 both years, at substation C in Quiver Lake, from June to 

 September, the maximum being in July, when it was also 

 seen in the river. A single occurrence in this lake in Decem- 

 ber is also noted. At one time I watched a Mast'Kioccrca. 

 feeding on some Spiroiiyra. It would jDuncture the side of a 

 filament with its sharp trophi and eat the green contents of 

 the cell ; then it would creep along, open another cell and 

 appropriate its contents ; and so on, until satisfied. 



46. M. elongata Gosse. 



Found l)ut once, in a towing taken below the surface of 

 Quiver Lake in June. 



47. M. bicornis Ehrbg. 



I found this species several times in the towings during 

 June and July, and again in November, mostly in Quiver 

 Lake, but in June also in oblique towings from the river at E. 



48. M. stylata Gosse. 



This form was scarce, being found only in towings from 

 the Illinois Eiverin August, 1895. 



49. M. bicristata Gosse, 



This species and .V. carinata yvere the commonest represen- 

 tatives of the genus at the Station, il/, hicristata was found 

 but once in the river, in September, but appeared in moderate 

 numbers in Quiver Lake from May to August, and in Thomp- 

 son's Lake from August to October. 



The specific characters as given by Gosse are, "Two equal 

 subparallel carina;, running nearly the whole length of the 



