62G dr. j. s. bowerbank on the spongiadjE. [May 7, 



Falco polyagrus (Cassin). (Prairie Falcon.) 



This egg, as might be expected, closely resembles that of Falco 

 jugger, and was found by my correspondent Mr. L. E. Ricksecker 

 at the head of Echo Canon, in Watsatch Mountains, Utah, U, S., 

 May 23, 1868. He writes me :— 



" The nest was placed in a niche at the top of an isolated rock 

 about 20 feet high, and had evidently been used by the same or by 

 some other pair of birds for a number of years, as it had the usual 

 appearance of old Crows' and Hawks' nests. It was much flattened, 

 and the materials were earth and sticks. It contained four eggs, 

 which were nearly fresh, incubation having barely commenced. The 

 altitude of the Canon at the place where the nest was located is over 

 6500 feet above the level of the sea; and the weather even at that 

 late date had not become settled, snow-squalls being of frequent 

 occurrence for more than another week. 



" I spent the whole summer of 1871 near this place, and I believe 

 we had some frost during every month. I saw both the parent birds, 

 and secured the male, which I forwarded to the Smithsonian Insti- 

 tution ; and Professor Baird told me it was the first adult male skin 

 he had received." 



Elanoides furcatus (Linn.). (Swallow-tail Kite.) 



Of this species I have the pleasure of exhibiting seven eggs taken 

 from four different nests. They were collected in Black-Hawk 

 County, in the State of Iowa, U. S. A. ; and my correspondent in- 

 forms me that in that locality the eggs are found from May 22nd to 

 June 8th ; and, so far as his experience tells him, the complement of 

 eggs is always two. 



The nests are built of sticks and moss, and are generally placed 

 in high trees. 



Ictinia mississippiensis (Wilson). (Mississippi Kite.) 



This rare egg was collected by one of the correspondents of the 

 Smithsonian Institution, Washington, U. S. A. The nest, composed 

 of only a few sticks, contained two eggs, and was found on the 12th 

 of June in a tree about ] 5 feet high ; and one of the parents was 

 secured. 



11. Contributions to a General History of the Spongiada>. 

 By J. S. Bowerbank, LL.D., F.R.S., &c.— Part III. 



[Received April 11, 1872.] 



(Plates XLVI.-XLIX.) 



Geodia tuberculosa, Bowerbank. (Plate XLVI.) 



Sjjonge massive, sessile, somewhat cup-shaped. Surface abound- 

 ing in large tubercular prominences ; i'urnished abundantly with ex- 



