8 Journal of the Mitchell Society [October 



The eruptions of Mt. Katmai, Alaska, in 1912, of Krakatoa, Sunda 

 Islands, in 1883 and of various other mountains have proved that 

 volcanic ash is sometimes deposited in beds of considerable thickness 

 a hundred miles or more from its source. In the Great Plains region 

 of the United States, the deposits of this material are thicker and its 

 texture coarser toward the west and thinner and finer respectively 

 toward the east which indicates an origin in the region of the Rocky 

 Mountains. In age they range from the Oligocene to the Pleistocene 

 and later. 



Examples of indurated tuffs occur in Michigan, Massachusetts 

 and IsTorth Carolina among the Pre-Cambrian rocks labeled in mu- 

 seums with such names as petrosilex, hornfels and novaculite and 

 also among those called flint-like slates and silicified tuffs by some 

 Avriters. 



Recent Mosquito Control Work in North Carolina. P. W. Leiby. 



Brief outline of diseases known to be transmitted by mosquitoes, 

 with emphasis upon those occurring in ISTorth Carolina. Resume 

 of control work done in ISTorth Carolina with account of antimalarial 

 operations at Wilmington, IST. C. Illustrated with lantern slides and 

 motion pictures, 



8ome Notes On Protozoa. Bert Cunningham. 



(a) The occurrence of Tintinnus serratus Kofoid, in Chesapeake 

 Bay, is printed in full elsewhere in this Journal, (b) Arcella ex- 

 cavata, nov. sp., most nearly resembles A. curvata Wailes, but is 

 characteristically different. Illustrated by lantern. 



The Ovary of the Gajf -Topsail Catfish, Felichthys felis. E. W. 



GUDGER. 



This organ is composed of two sacs separate in front but united 

 posteriorly to form a common oviduct opening on the genital papilla. 

 The walls of the posterior or oviducal third lie in parallel ridges to 

 allow for the distention necessary in the passage of the great eggs 

 averaging 20 mm. in diameter. These ridges decrease in height 



