92 



METAZOA continued. 



Spongise. 



Myxospongise, o. m. 



Ceraospongise, o. m. 



Monaxonidas, / m. 



Tetractinellidae, o. m. 



Hexactinellidse, o. m. 



Calcispongiae, o. m. 



Monazonidce. 



Renieridse, /. m. 



Chalinopsidse, o. m. 



Desmacidinse, o. m. 



Suberitidse, o. m. 



RenieridcB. 



A large number of sub-fa- 

 milies not yet defined, o. m. 

 Spongillinse, /. o. 



Spongillmw. 



Section a with statoblasts. 

 Ephydatia, 

 Euspongilla, 

 Tubella, 

 Parmula, 



*Section b without statoblasts. 

 Lubomirskia, 

 Potamolepis, 

 Uruguaya, 



SOLLAS On the Origin of Freshwater Faunas. 



Ccelenterata. 



Hydrozoa, 

 Actinozoa, 



Hydrozoa. 



Hydromedusa, 

 Siphomedusse, 



f.m. 

 o. m. 



/. m. 

 o. tn. 



Hydromedusce. 



Grymnoblastica-anthomedusse, /. m. 

 (Hydra and Cordylo- 

 phora are the only fresh- 

 water forms in this 

 group.) 



Calyptoblastica-leptomedusa, o. m. 



Trachomedusse, / m. 



(Lymnocodium is the 

 only described freshwater 

 genus in this group.) 



Narcomedusae, o. m. 



Hydrocorallinse, o. m. 



Siphonophora, o. m. 



Polyzoa. 



Ectoprocta,f o. m. 



Entoprocta, /. m. 



Gymnolaemata, /. m. 



Phylactolsemata, /. o. 



* This section was instituted by Dr. Win. Marshall (Ann. and Mag. Nat. Hist. 1883, ser. v. vol. xii.) ; 

 but with the exception of Lubomirskia, the alleged absence of statoblasts is asserted on negative 

 evidence of an incomplete character. Lubomirskia lives in Lake Baikal. Potamolepis inhabits the 

 Congo, occurring as far up as 150 miles by water from the sea, and over 100 metres above its level, 

 with several cataracts intervening. Marshall also mentions Spongilla stygia, a transparent sponge, 

 living in the Grotto of Gurk in Carniola, as being devoid of statoblasts. 



Those freshwater sponges which do not form statoblasts are the exception: the vast majority of the 

 SpongillinsB, world-wide in distribution, are characterized by the occurrence of these structures. 



t The Ectoprocta are usually regarded as exclusively marine ; but exceptions are recorded. Semper 

 quotes the following : Membranipora bengalewis, Stol. ; Victorella pavida, Kent (Animal Life, p. 486). 



The Gymnolsernata are almost exclusively marine. Paludicella is the only exception known in this 

 country. Prof. Haddon regards it as a comparatively late immigrant. Haddon, "On Budding in 

 Polyzoa : " Quart. Journ. Micro. Sci., vol. xxiii., N. S., p. 551. 



