CHAPTER SIXTH. 



ENUMERATION AND GEOGRAPHICAL DISTRIBUTION OF THE DISC0PH0R.5:. 



SECTION I. 



TABULAR VIE\y OF THE DISCOPHOR.E KNOWN AT PRESENT. 



In the following enumeration, I have only quoted the most important references, 

 and only those in full from Avhich the most accurate knowledge of the species 

 may be obtained. The other references may be found in Eschscholtz and in 

 Lesson, whose general works on Acalephs must be in the hands of all those who 

 study these animals. 



Order of DISCOPHOR^ ^5e//. : Medusarias Zmk. 1816 (pro parte). — M^duses Per. 

 and LeS'. 1809 (p. p.). — Acalephes Simples Ciiv. 1817 (p. p.). — ^quorejB 

 OoM/. 1820 (ix p.). — Medusa? Cham, and Ez/senk. 1821 (p. p.). — Cyclomorpha 

 LcUj: 1825 (p. p.). — Discophoraj phanerocarpte Usch. 1829, and cryptocarp^ 

 i:,ch. (p. p.).— Pulmograda Bl. 1830 (p. p.). — Medusidaj Br. 1833 (p. p.).— 

 MedusjB Less. 1843 (p. p.). — Steganophthalmata Forbes, 1848. — Acraspeda 

 Geffenb. 1856, and Craspedota (p. p.). — Discophoroe At/., see page 3 of this 

 volume, where the natural limits of this order are more fully discussed. 

 1st Sub-order. RHIZOSTOME^ Aff., see pp. 9 and 131 of this volume. — Rhi- 

 zostomidifi Bseh. 1829. — Polystomaj Br. 1833. 



1st Family. RmzosTOMD.iD Aff. {Esch. p. p.). The family of Rhizostomida?, 

 as here circumscribed, contains only those Rhizostomeje in 

 which the actinostome is composed of four pillars, between 

 which open the four genital pouches, and from which hang 

 eight simple arms, with numerous lobes of the marginal folds, 

 extending along the greater part of their length, but without 



