AMERICAN HYDROIDS. 



SECTTOTsT 2.-THE SERTTJr^YI jm. K. 



EUR ATA. 



j 4*1, 7th lino from top. <//////<//// /<,/ should lie cylindrica 

 . -e 4'>, ^d line from bottom. f<iit><ir!xl;i should bo tamarisca. 

 1'ao-e HI. ">'.itli line from bottom, 77 should be 77o. 

 1'ao-e :,(. 7(h line from bottom, x, r> iilnr!i<l> x should bo /w///// 

 1'ao-o 77, :!(ltli line from top. ,ill>,i sliould bo ,ill>'nl,i. 

 1'ao-o 77. 4th lino from bottom, yuadridens should lie yuadrifida. 

 1'ao-o |()L>, last footnote, p. l*7ii should be 1>. 'Ji'l. 



II II I . 



I'll iril. Sucli invesSgations ;is have just boon referred to led to a nvneral understanding of 



the morphology of the Ilydroidu as a whole, and. as the Scrtularid.-e otl'rred little that a|)peai-ed 

 to lie novel, that family was naturally passed by in favor of groups oH'erini;' more inlerestinjr. 

 because more novel, structures for investigation. 



The writers who have contributed most to our knowledge of the morphology of this family, 

 purely systematic work beiny excluded, are the following: Louis A^a>six. \\lio e-ivos an excellent 

 and superbly illustrated account of >'. rtnlnri<i //////A/: :1 Allman.' who discu-ses the ^onosome of 



1 Ann-rii-aii llylnii.ls. I'nrl I, The I'lninuhiriil:. . 1900, p. :',. 



While tlii." is true when the Sertuhiriil;r and I'luinlllaridir are I'liinpureil. il 1>\ im means fullnws that the 

 Sfrtnlarid:r are "f I' >\v rank \\ hen i-(iin|iare,l \\ilhthehydrniilsin jiencral. [ndeed, quite the Opposite 18 true if we 

 admit the view in>\v very retu'rally adnpl..! thai the sessile .u''m<ii>lic>rc* reprewnl di-_'raded medusa-. This nuilter, 

 however, will lie disenssrd later. 



M'.intrilmtidiistn the Natural History of the rnil.'.l States, IV. Isii'J, p. .".L'ti. 



'Monograph of the Gymnoblastic Hydroiils. isri. p. :.n. 



