X8 AMERICAN HVDROIDS. 



In comparing the above with the table showing the geographical and bathymetrical distribution 

 of the Eleutheroplea we find that the proportion which the West Indian forms bear to the whole 

 number of species is identical in the two groups. In both of them 75 per cent of all the species 

 are found in the West Indian region. The Statoplea are more abundantly represented on our 

 North Atlantic seaboard than the Eleutheroplea, there being 15 species ('.'(I per cent) of the former 

 to 9 species (17 per cent) of the latter. Only 5 (7 per cent) of our American species of Statoplea 

 are represented in Europe, while 5 (10 per cent) of the Eleutheroplea are found on the European 

 coasts. But in each case several genera are represented. In both groups a single species is com- 

 mon to both the American (Pacific) and Australian fauna-. 



In the bathymetrical distribution a similar comparison shows that of the Statoplea 52 species 

 (75 per cent) are found inside of the 100- fathom line, while in the Kleutheroplea there are .">4 species 

 (05 per cent) found in the same limits. In the Statoplea a single genus is confined to a depth 

 greater than 100 fathoms, while there are 2 of these deep-water genera among the Eleutheroplea. 



In the Statoplea 5 species have been dredged from a depth greater than 500 fathoms, the 

 deepest being 1,742' fathoms, while in the Eleutheroplea only one such species is recorded found 

 at a depth of 570- fathoms. 



KEY TO TIIK (iKNERA OK STATOPI.KAN I'LI'M I I. ARID. K. 



Gonosoiiie . < 



Corbul;r, each of which is a iiin<lilie<l 

 hydrocladinm. 



Protective branchlcu. each of which 

 is an appendage to a hydrocladiuui. 



Lateral marginal teeth not inconspicuous; no hydrothera at 

 base of cadi gonaiigial leaf Iglaoplimia. 



Lateral teeth inconspicuous; a hydrothcca at base of each 

 gonaogial leaf Theeoewpus. 



Two pairs of lateral nematophores to each hydrotheca. 



( 1'eiitandra.) 



Distal hydrocladia replaced by spine-like processes; an ante- 

 rior in trathccal ridge (Acanlhocladium. ) 



C'anline nematophores not very large, or, if large, not dis- 

 tinctly crennlatco 1 ; phylactogoniuui not jointed. I'ludocurpns. 



('iniline uriiiatophnres largo and crenulated; phylactogouinm 

 jointed, often with hydrotheose tglaophenopsis. 



Protective bram hlets, each of which ^ Stem fascicled; a prominent perforated process at the base of 



is a modilied hydrocladinm. 



Gouaugia without protective contriv- 

 ance of any kind. 



each by drocladium Lytocarpus. 



Supraealycine sareothecie wanting (Kirchenpaueria.) 



An anterior intrnthecal ridge; no septal ridges in hydroeladial 



iuternodes Halicornnna. 



No marginal teeth; hydrocladia branched Nwditheca. 



Hydrocladia arranged in a spiral around the stem. 



Streplocaitlns. 



Hydrothecal wall reduplicated. No supracalycine nematophores (Diploclieilus.) 



AGLAOPHENIA Lamouroux ("modified). 

 CALATHOPHORA isubgenus) Kirchenpauer. 



Trophosome. Stem not fascicled in American species; hydrothecal margin dentate; a posterior 

 iutrathecal ridge present and usually well marked; two supracalycine and one mesial nemato- 

 phore attached to each hydrotheca. 



(iunosome. Gonaugia inclosed in a true corbula formed of a modified pinna, its leaves without 

 hydrotheca- at their bases. The corbula may be either open or closed. 



This genus as originally described by Lamouroux :l included all known Plumularida- except 

 the genus Nemertesiu = Anteutnilaria. In 1857 McCrady 4 restricted the genus to the forms now 

 embraced in the Statoplea, in which he was followed by Agassi/ 11 in 1802, and Ilincks 11 in 1808. 

 Kirchenpauer 7 in 1872 divided the genus into four subgenera, Culutltopltora, Parhyrhynchia, 



1 Aglaopltenopsis rerrilli. 



- I'lumnlaria alternata. 



1 Bulletin SociiHe Philoniatique, 1812. 



1 Gymuophthaluiata of Charleston Harbor, p. 200. 



''Contributions to the Natural History of the United States, IV, p. 358. 



'British Hydroid Zoophytes, p. 284. 



'Ueber die Ilydroidenfamilie I'liimiilarida-, Pt. 1, Aylaoplienia, p. L'5. 



