Miscellaneons. 333 



not be certain) in which the statospheres are segregated into groups 

 of four or more, spherically enclosed in a similar coating, thus 

 appearing like one large seed. While the statohlasts of the former 

 arrangement retain their positions during the winter and germinate 

 there in the spi'ing, it may be that this is a character assumed for 

 diffusive propagation. 



In Sjiontjilla lacustris and similar branching sponges, the appar- 

 ently conflicting ends of retention and diffusion are attained in a 

 dihereut way. The " seed " are formed in the interstices of both 

 the sessile and the branching portions. In the former they are 

 retained during the winter, partially by the agency of recurved 

 spines upon the acerates pi'ojecting from the seed-coat ; while the 

 fragile branches soon break off and float their contained statospheres 

 to distant parts. 



The massive sessile character of many sponges, repeated through 

 various forms of Spoiu/illa and Alcyeiiia, partially protects their 

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

 protection fails them, the rays of the birotulate spicules of the 

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

 a sulncieut number until the time of germination in the spring. 



Three species of American sponges have been grouped tinder the 

 generic name .Heteromtyenia, 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 framework of 

 two of these species is altogether filmy and fugitive ; the stato- 

 spheres are not held within the interspaces of the skeleton or 

 retained in any other way, 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 Carterclla 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 occasioned by the 

 looseness of their skeleton-texture, from -which the sarcode-flesh 

 dying early washes away, most of the sjncules soon following in the 

 winter floods. The eggs are thus left to the protection of the above 

 tendrils, which lap them together, bind them to the remaining 

 spicules or the rooLs of water-weeds or shore-plants ; or, assuming 

 the role of the hair the plasterer usrs, bind the deposited silt about 

 them and both to the stones, where they await the a})pointed time 

 for a new growth. This function is very clearly shown in the 

 collection in Mr. Potts's possession ; and the resemblance in material 

 structure of these tendrils to that of the specialized hooks of the 

 forma of Polyzoa referred to is very .striking. He hopes there- 

 fore 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. — Proc. Acad. 

 Nat. Sci. rhUad., Dec. 6, 1881. 



