204 ACTlNLi: OV Al-BATKOSS KXl'l.OKATlONS — M'MirKKR'lI. 



Part 111. 



geographical and bathymetrical distribution of the actiniaria. 



To anyone who has sln<li«'(l the habits of Actinians tho deiKMuliMioe 

 of the various species upon their surround in. us is very evicU'nl. ISouie 

 are to be found oidy on rocky sliores, others prefer sandy bottoms, 

 Avhih^ others asiain make their homes only in ninthly Hats. Some bury 

 themselves in the sand or nnnl so that only the disk and tentacles pro- 

 trude, others are to be found oidy on yasteropod shells iidiabited by 

 Hermit Crabs, while otliers ayain lirmly clas]) stems of (btruoidans. 

 In other words, nearly e\ ery species has a more or less detinite habitat. 



Furthermore, as a rule the various species have a more or less deti- 

 idte distribution, so that it is possible to mark out nu)re or less detniite 

 jicoj^raphical regions characterized by their Actinian fauna. Thus the 

 eastern coast of the United States presents three fairly well delined 

 re.u'ions so far as tin* ^Vctinian fauna is concerned. North of ('ape(\>d 

 we have what may be termed the lioreal region, characterized by the 

 occurrence, among other forms, of Tvulia crass icornis, Metridiiim mar- 

 (/inatiini. and Ccridntlnis horcalis \'err. Secondly, there is what Verrill 

 has called the Nirginian region, which includes the ^'irginian and Caro 

 linian coasts, and probably (Jeorgia to tlie south, and Delaware and 

 l)art of New Jersey to the north. clKuacterized by the presence of /*////- 

 iHdctis caroiiatd, AddDisid sol, and ('iiidiithiis (Dnciicaiiiis iwnowiiothvvs; 

 and lastly, there is the Florida region, characterized by forms identical 

 with those of the West Indies. Northein New Jersey and Long Island 

 Sound constitute an intermediate region ])ossessing forms such as 

 Mi'lridiioii ))inr<i'nt<tlii)ii. I'caeliing their most ]>erfect develoiuni'ut in the 

 IJoreal regi<»n, and others, such as FJoadls {HdJctDHjxt) pvodnvid and 

 I'drdclis rdpil'oniiis, which belong ])roperly to the \'irginian region. 



^^ lu'u tlu' distribution of genera is considered, however, this detinite- 

 uess, as might be exj>ecte«l, becomes more or less indistinct, though 

 even Mith some of these distinct areas of delimitation can be estab- 

 lished. With the larger groui)S the same holds true, aud even when 

 the orders are considered a certain amount of limitation of their dis- 

 tribution can be determined. The Actinina', it is true, have a world- 

 wide distribution, but, as 1 have ])ointed out ('81)), the Stichodacty 

 lina'. though of wide distribution, have their headtpiartersin the I'aeilic 

 and West Indian regions, and it maybe said in the regions of coral 

 formation. 



Our knowledge, however, of the A<'tinian fauna of a griMt deal of 

 the Paeitic and Indian Oceans and of the S<mth Atlantic is as yet very 

 slight, aud'it is hai<lly time to enter into an t'xhaustive disenssitui of 

 the geogra])hical distrilmt ion (tf the larger groups, families, and or«lcrs 

 of the Actinaria. So far as the .1 //xf/rew collection is concerned, there 



