1881.] NATURAL SCIENCES OF PHILADELPHIA. 463 



various forms of Spongilla and Meyenia^ partially' protects their 

 statospheres from the accidents of the winter season, and when that 

 protection fails them, the raj'S of the hirotnlate spicules of the 

 latter and the curved acerates of the former, come in play to 

 retain a sufficient number until the time of germination in the 

 spring. 



Three species of American sponges have been grouped under 

 the generic name Heterovieyenia^ characterized by the presence 

 of a second form of birotulate spicules interspersed amongst the 

 more familiar series. These are about double the length of the 

 former and are terminated by long recurved hooks. The frame- 

 work of two of these species is altogether filmy and fugitive ; the 

 statospheres are not held within the interspaces of the skeleton 

 or retained in an}- other waj', and are therefore dependent upon 

 the above hooks for their attachment to proper bases for future 

 growth. 



Completing the series of retentive agencies we find the stato- 

 spheres of the three species of the disputed genus Carterella 

 provided, in addition to their birotulate spicules, with long curling 

 or twisting tendrils, extensions, as we have heard, of the tough 

 chitinous coat. These are required to meet the emergency occa- 

 sioned by the looseness of their skeleton texture, from which the 

 sarcode flesh dying early washes awa}', most of the spicules soon 

 following in the winter floods. The eggs are thus left to the pro- 

 tection of the above tendrils which lap them together, bind them 

 to the remaining spicules or the roots of water weeds or shore 

 plants ; or, assuming the role of the hair the plasterer uses, bind 

 the deposited silt about them and both to the stones, where they 

 await the^ppointed time for a new growth. This function is very 

 clearly shown in the collection in Mr. Potts' possession, and 

 the resemblance in material structure of these tendrils to that of 

 the specialized hooks of the forms of Polyzoa referred to, is very 

 striking. He hopes therefore, that as both analogy and observed 

 facts seem to indicate the correctness of his position, Mr. Carter 

 will be willing to accept the compliment intended and which is so 

 well deserved. 



December 1.3. 

 The President, Dr. Ruschenberqer, in the chair. 

 Twenty -three persons present. 

 The death of Ami Boue, a correspondent, was announced. 



Piloholns crystallinns. — Mr. Thomas Meehan remarked that 

 this small fungus had proved this season to be an expensive 

 annoyance to florists engaged in winter forcing flowers. Rose- 



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