128 



EYDROZOA. 



Sertularidce are identical with European forms 

 both being, in a large number of cases, sufficiently 

 distinct from the Australian, Phillipine, and New 

 Zealand species. Several British species cannot, 

 however, be distinguished from those of the Atlan- 

 tic coasts of America, while on the other hand, 

 greater differences prevail between these last and 

 the North Pacific forms. Among purely exotic 

 genera may be mentioned Cryptolaria, one species 

 of which has been found in Madeira and another 

 in New Zealand, and Lineolaria, a remarkable 

 Australian Sertularid, having gonophores y with two 

 longitudinal rows of strong spines elevated in ridges, 

 between which a few smaller spines are scattered 

 over a flattened, transversely furrowed area. 



The Calycophoridce and Physophoridce have 

 hitherto been most successfully studied in the 

 Mediterranean and Southern seas ; some genera, 

 such as Diphyes and Agalma, having been obtained 

 by Sars at a latitude of 6i^° N. off the shores of 

 Norway. It were premature to describe any of 

 these forms as peculiar to certain regions, many of 

 the species and genera ranging over areas of consi- 

 derable magnitude. 



Precise information is much wanting on the dis- 

 tribution of the Medusidce and Lucernaridw. 

 The free zooids of some species are very extensively 

 diffused, and are occasionally met with by sailors 

 in numbers so immense as almost to impede navi- 

 gation. Our common Aurelia aurita has been 

 obtained in the Red Sea, off the east coast of North 

 America, and in various parts of the southern 

 hemisphere. 



A few words on the phosphorescence of the 





