1887,] NATURAL SCIENCES OF PHILADELPHIA. 177 



(4) Troohospongilla erenaceus, Ehrenberg. 



Syn:— 

 1846 Spongilla erenaceus, Elireiiberg. 

 1856 " " Lieberkuhn. 



1877 " " Vejdovsky. 



1881 Meyenia " Carter. 



1883 Trochospongllla erenaceus, Vcjdovsky. 



1883 Spongilla " Retzer. 



1885 Trochospongllla " Wierzejski. 



Trochospongilla is of considerable dimensions, covering foreign 

 bodies in cushion-like incrustations ; of a whitish or straw yellowish 

 color; skeleton spicules sharply pointed at both ends ; surface, except 

 at the extremities, covex-ed Avith powerful spines. Parenchyma spic- 

 ules, correspondingly (?) small, smooth, and very often swollen in the 

 middle. Gemmulre covered with spool-like amphidiscs whose rotules 

 have entire margins. They lie at the base of a deep air-chamber- 

 layer which consists of radially placed hollow columns, that are 

 divided into a number of chambers by cross-partitions. 



Trochospongilla erenaceus has been observed in many places in 

 Europe. In Germany by Ehrenburg; in Bohemia by Vejdovsky; in 

 Galicia by Wierzejski, and in Russia by W. Dybowski. 



(Ill) Gen. EPHYDATIA (Jray. Lamaiek. 



Skeleton spicules either entirely smooth or entirely rough ; though 

 sometimes both forms are j)resent together. In the air-chamber- 

 layers, around the gemmula?, are embedded amphidiscs with star 

 shaped rotules, in one, two or three layers placed one over the other. 

 In the first instance they may be of equal length, but frequently 

 their lengths are unetjual. 



(5) Ephydatia mlilleri, Lcibeikiihn. 



Syn:— ^ 



1816 Spongilla pulvinata, Lamarck. 

 1856 " mulleri, Lieberkuhn. 



1877 " " Vejdovsky. 



1878 Trachyspongilla mulleri, Dybowski. 



1882 Meyenia laio. 2. 



1882 Ephydatia No. 2. 



1883 " millleri, Vejdovsky. 



From A. Form B. var. astrodiscus, Vejdovsky. 

 1883 Ephydatia amphizona, part. 

 1883 Spongilla mirabilis, Retzer. 



1885 Meyenia mulleri, Wierzejski. 



1886 Ephydatia " Petr. 



