174 PROCEEDINGS OF THE ACADEMY OF [1887. 



bound into fascicles, which are either long threads, or are placed us 

 a network in the tissues. Hooked spicules cover the gemniulse aud 

 are widely dispersed through the tissues. They live in ponds and 

 quiet flowing water and appear to he the most widely distributed spe- 

 cies of Germany." 



Although from this description of Retzer's it is evident that ;Spo/<- 

 (jllla lieberlcuhuil oidy slightly diifers from his S. laeustris, I thought 

 it necessary to examine for myself the nature of the form in question. 

 From a small fragment of S. lieberkuhnU for which I must thank 

 Prof. Eimer, I clearly recognize its identity with S. laeustris. In 

 the form of the gemmulse and the scarcity of the covering spicules 

 I find no difference between them ; sections of the gennnuhe j)rove 

 that the air-chamber-layer is more or less developed and its surface 

 may be with or without a horny membrane ; which is also the case 

 with Eitspongilla laeustris in various localities in Bohemia. 



The immense, even predominating quantity of the strong, rough 

 parenchyma spicules, and an equally large number and variety of 

 the external form of the gemrauhie spicules — these are, on the other 

 hand, the striking characteristics which strongly suggested the re- 

 cognition of a similar form from the Jordan Pond, near Tabor, in 

 Bohemia, as a distinct species, {Empongilla jordanensis). But the 

 quantity of sponge material that has been at my disposal for some 

 years, convinced me otherwise. In some specimens from the Elb, 

 near Koniggnitz and from a pond near Poiakek (?) I found the 

 gemmul?e and covering spicules to correspond with each other, and 

 with the characteristic type of S. laeustris ; while in single branches, 

 they were identical with the same features in E. jordanensis, from 

 the Jordan Pond ; and at the same time a corresponding quantity 

 of rough parenchyma spicules was found in its tissues. We must 

 therefore unite E. jordanensis with E. laeustris. 



E. laeustris, var. macrotheea, very nearly resendiles the following 

 species. — 

 (2) Euspongilla rhenana. Ilutzei-. 



Syn. — 1883 Sponf/ilki rhenan<f, Ketzer. 



This iuteresting species was first described by Retzer in the fol- 

 lowing terms: — "Itditters from the other species by the smooth gem- 

 multe spicules." 



"It encrusts pieces of wood, bushes and the like, sending out a 

 few small processes ; and also in many places forms tliick masses. 

 The skeleton s[)icules are straight or slightly curved, abruptly or 



