156 DISTRIBUTION. 



of the North Atlnntic have yielded others of much interest ; and others still have Ijeen found 

 tenanting the great Nortli Atlantic seaweed meadow, where, borne upon the floating weeds of the 

 Sorgasso Sea, they lead alnmst the pelagic life of the planoblast.^ 



Some scanty observations have come to us from the Pacific and Atlantic shores of South 

 America, from the Falkland Isles, from Madeira, from the Islands of the East Indian Archipelago, 

 and from Kerguellan's Land, and the Auckland Islands ; while we have somewhat fuller ones 

 from the West Indies. From all these localities we have evidence of the occurrence of hydroid 

 life, though from none have we data sufficient for the determination of definite hydroid provinces. 

 We have hardly yet sufficient information to enable us to assign any special physiognomical 

 facies to the hydroid faunas of special zones, though the beautiful plumnlarian group represented 

 by the genus JgJaophenia may be considered as especially characteristic of intertropical and 

 warmer temperate seas, where it acquires a far greater development than in the colder w^aters of 

 the higher latitudes ; and it may perhaps also be asserted that the largest hydroid forms are as a 

 rule confined to the w'armer seas, while those of temperate and colder latitudes consist for the 

 most part of hvmibler and less conspicuous species. 



Under the name of Phmidaria angiilosa Dana" mentions a hydroid from the East Indies, 

 which attains a height of three feet, while Semper' has described a gigantic plumularian hydroid 

 from the Pelew Islands, where it forms submarine forests nearly equalling in height that of a man, 

 and with the base of the stems more than an inch in thickness. It is armed with formidable 

 stinging cells, and the incautious bather will have reason to repent his too rash incursions 

 within the precincts of this marvellous grove when he finds himself suffering for hours afterwards 

 a sense of intolerable burning excited by the envenomed darts to which he has unwittingly 

 exposed himself. 



Nothing which can be compared with this has been found in any of our northern or 

 temperate seas, where, however, Ac/laophenia mi/riophi/lhim may attain a height of between two and 

 three feet, and where Tubiilaria and Corijmorpha present forms which strike us by the large 

 size and conspicuous beauty of their hydranths. 



The genera of the Hydroida would appear to be far less rigidly confined within limited 

 areas of distribution than we know to be the case with those of other nearly allied groups, such 

 as the coral-forming Advnozoa. 



In a collection from New Zealand, which was placed in my hands for determination by Mr. 

 Busk, and which consists of twenty-five different species of calyptoblastic hydroids referable to 

 seven genera, I cannot find more than two generic forms (both new) which are not also British. 

 Among thirty-one species from Australia, collected during the voyage of the " Rattlesnake," 

 referable to seven genera, and determined by Busk,* five of these genera are, as pointed out by 

 Busk, represented by British species, while of the remaining two {Paxythea, Lamx., and Idia, 

 Lamx.), Pmijthca, though not British, is according to Lamouroux, a form belonging to the 



^ Suice the above was writteu the Hydroida obtiiined during tlie e,\ploration of the Gulf Stream 

 by tlic United States Coast Survey have been entrusted to me for determination. So far as I have as 

 vet been able to e.xamine tliem I find tliem full of interest. Tlie collection is a very large one, and 

 gives promise of a most important addition to our knowledge of hydroid zoology. 



' Dana, " Structure and Classification of Zoophytes.'' 



' Semper, 'Zcitschrift f. w. Zool.,' Bd. xiii, p. 560. 



* Busk, in the Appendix to the ' Voyage of the Battlcsuake,' p. 385. 



