4 PEOCEEDINGS OF THE NATIONAL MUSEUM vol.82 



Remarhs. — The two types of skeletal spicules and the two types 

 of flesh spicules readily establish the new species. The two types of 

 flesh spicules resemble closely the gemmule spicules of Eeteromey- 

 enia ryderi haleni found in the same pond (Penney, 1931). It was 

 at first thought that they were identical and that the HeteroTneyenia 

 spicules had been deposited in the parenchyma of the Spongilla. 

 This idea, however, was soon given up, as the spicules are present 

 in abundance in all the Spongillas examined. As a final proof, 

 young sponges grown from the " reductien " (reduction bodies) of 

 Mliller (1911) show both mature spicules of these types and many 

 developmental stages. 



There are no gemmules heretofore described that are in the shape 

 of a discus or in which the two chitinous coats are applied to each 

 other over a greater part of the surface, or in which the granular 

 zone is restricted to a particular portion of the gemmule. For a 

 proper understanding of the true relationship of the chitinous coats, 

 it will be necessary to study developmental stages. According to the 

 diagnosis of the genus Spongilla given by Potts (1887), the gem- 

 mules are surrounded by spined acerates and the skeletal spicules 

 are rarely spined. Gee (1930) gives a list of the known fresh-water 

 sponges. Of these, reference to one genus only is probably neces- 

 sary. Annandale (1913) describes the gemmules of Nudospongilla 

 as " devoid of foramina, pneumatic coat and spicules, adherent at 

 the base of the sponge, ovoid in outline and somewhat flattened." 

 In the description of the type, N. coggini, he states that " gemmules 

 of moderate size, few in number, flattened at the base, dome-shaped 

 above, with a central indentation or concavity; their chitinous coat 

 thin and brittle, covered by a delicate outer membrane in continuity 

 with the basal membrane of the sponge." A new genus may be 

 indicated, but until more sponges of a similar nature are described, 

 it is better to consider this sponge as a greaHy modified Spongilla. 



This sponge has been reported before by the author (Penney, 

 1931) as an unidentified species of Spongilla^ but it was not de- 

 scribed. As stated above, collections were made throughout the 

 year. During the summer of 1932 gemmules of this sponge were 

 found in abundance floating at the surface of the pond. It is quite 

 probable that this indicates the disintegration of a great number 

 of sponges, as the pond, because of an extraordinary dry season, 

 was greatly reduced in size, the shore line having retreated about 20 

 feet during the summer. Many of these floating gemmules were 

 empty. No gemmules were observed in the process of liberating 

 their contents, but the method by which this is done might be in- 

 ferred from the appearance of the empty ones. A portion of one 

 side of each gemmule, not including the granular zone, was lacking 



