594 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.40. 



spines of the longer gemmule spicules, for in A. plumosa these spines 

 have a simple curve, while in A. radiospiculata the tips are distinctly 

 recurved so that the whole spine as seen in profile has almost the 

 form of a capital J. 



Both of these species appear to be rare. A. radiospiculata was 

 originally described from Cincinnati, Ohio, and some fine specimens 

 have recently been acquired by the U. S. National Museum from 

 Granite City, Illinois. The largest of these specimens, which were 

 obtained by Mr. B. Donaldson in the settling tanks of the city 

 waterworks in August, 1910, measures no less than 42 by 12 by 8 cm.; 

 they are all, in a dry condition, of a dark gray color. The only lo- 

 cality whence A. plumosa was hitherto known was Pinto Creek, 

 Kinney County, Texas, but a very beautiful specimen from Shreve- 

 port, Louisiana, has recently been added to the National collection. 

 It is almost circular in outline, nearly flat, and of a pale brown color 

 in the dry state, measuring 28.75 by 24.7 cm. Both it and a speci- 

 men of TrochospongUla leidyi found with it are permeated by the 

 tubes of a bryozoon of the genus Plumatella. It was obtained, like 

 the gigantic specimen of A. radiosjriculata to which allusion has 

 been made, from the settling tanks of the city waterworks, a situa- 

 tion which might be expected to be favorable for the growth of 

 sponges. 



