70 Citicinnati Society of Xatiiral History. 



Genus 13. — Dvstactospongia, S. A. Miller, 1882. 



" This is a massive, more or less regularly hemispherical, 

 fixed, calcareous sponge. It possessed a frame work that rad^ 

 iated from one or more points of attachment, and bifurcated 

 without any determinable order, so as to constitute a great 

 part of the body of the sponge. The entire mass is vesicular, 

 the frame work being more dense than the intervening spaces. 

 Spiculse not a.scertained " (Jour. Cin. Soc. Nat. Hist., vol. 5, 

 1882, p. 42). 



Remarks. — Nothing further has been added to our knowl- 

 edge of this genus. 



I. D. ixsoLENS, S. A. Miller, 1882. 



" Sponge large, irregular, somewhat hemispherical, and 

 varying from two to four or five inches in diameter. The 

 architectural frame work radiates from several different points 

 of attachment, and divides and subdivides without order, and 

 constitutes more than two-thirds of the entire mass. As seen 

 under the higher powers of the- microscope, the structure is 

 vesicular throughout, and full of amoeba-like outlines which 

 may possibly represent spiculce * '^^ "■' * * 

 Under a power of 800 diameters the vesicles are observed to 

 contain numerous subcircular, subelliptical and amoeba-like 

 bodies, with irregular outlines, but I am not able to say that 

 the}' are spicukc or fragments of such forms." 



Locality. — Cincinnati, Ohio. 



2. D. MINIMA, Ulrich, i88g. 



" Proposed for a small parasitic sponge, apparently congen- 

 eric with n. inso/ens, S. A. Miller. It forms thin crusts or 

 small irregular masses upon bryozoa [polyzoa] and other for- 

 eign bodies. The largest seen is about 15 mm. wide, and 5 

 iiini. liigli at the centre. The canals are much smaller than 

 in any of the other species, and the partitions exceedingly 

 thin. Al)out five canals occur in two mm. The whole skele- 

 ton is usually replaced by a brown oxide of iron" (American 

 Geologist, vol. 3, 1889, p. 243). 



Locality. — Hanover, Butler Co. Ohio. 



Remarks. — This species, though parasitic, is con.sidered 



