1881.] NATURAL SCIENCES OF PHILADELPHIA. 461 



different methods of preparation, he had failed entirely to meet 

 ■with an instance showing similar appearances, he referred speci- 

 mens of all three species of the genus to Prof. Jos. Leid}^, whose 

 fame as an accurate observer is world-wide ; to Mr. Jno. A. Ryder, 

 and to Prof. Kellicott and Mr. Henry Mills of Buffalo, the 

 discoverers of one of the above species. The efforts of these 

 gentlemen were equally unsuccessful, their opinion being well 

 expressed in Prof. Leidy's words, " In my mind there can be no 

 question as to the tendrils being part of the structure of the 

 statoblast, and their parasitic nature would never have occurred 

 to me." " The tendrils are homogeneous extensions of the inner 

 capsule of the statoblast and I see no trace of the appearance to 

 which you refer in Carter's figure 2." A paragraph from the 

 letter of Prof. Kellicott makes a further point. These processes 

 " are not found on the statoblasts of any other species in the 

 Niagara River ; I have examined hundreds of the statoblasts of 

 Carterella tubisperma, and have not found one without said tube. 

 I brought some of these, having wintered in the river, to my 

 room last May ; after a few days, there was sponge growth ; so 

 this form if a parasite did not destroy the life, etc." 



The second point made by Mr. Carter was that the species 

 marked G. tuhisj^erma from Buffalo, was identical, as shown by its 

 spiculation, with one marked Heteroraeyenia repens from Lehigh 

 Gap, Pa. That one of these identical species should exhibit the 

 tubular prolongation and accompanying tendrils, while the other 

 did not, was considered presumptive evidence that the former was 

 affected in some abnormal way. To this Mr. Potts answered, that 

 while there was unquestionably much similarity in shape of the 

 birotulate spicules of the two sponges, covering the " seed bodies " 

 in the ordinary fashion as a second or outer coat, the Lehigh Gap 

 species alone exhibited the second class of long birotulates, inter- 

 spersed with the others, which had induced him to place it in the 

 genus Heteromeyenia. For this reason he believed the species 

 were not identical, and this argument fails. 



In continuation he reasoned that it should not be considered a 

 matter of surprise that the statospheres of some genei-a pertaining 

 to the family of fresh-water sponges, should present tentative 

 features of this character. In a paper published so long ago as 

 1859, Mr. Carter called attention to the resemblance in appearance 

 and function between the statoblasts of the Polyzoa and the 

 so-called " seed bodies " of Spongilla. The parallelism is rendered 

 more complete when we observe that in those forms of Polyzoa 

 possessing a comparatively rigid octocyst, the statoblasts are 

 circular or lenticular with smooth margins. Some of these are 

 no doubt washed out from the tubular body from time to time 

 during the winter, to extend the species to other places ; while 

 enough are retained b}^ it to renew the growth in the original 

 locality. On the other hand, where the body mass is simply 

 gelatinous, as in Pectinatella, Cristatella, etc., decaying away and 



