120 CLASS III. 



well as suctorial mouths : [they are single animals, in short, and not 

 colonies.] The projecting edges, usually named ribs (costce) which 

 are beset with cilia, especially characterise this family : whence the 

 German name Rippenquallen. Whether these vibratile cilia, whih 

 occasionally are so arranged as to form vibrating laminae, do really 

 cause the progression of these animals, as is usually assumed, is in 

 consequence of the objections raised by MERTENS and by WILL 

 (Iforce Tergest. s. 8 13) exceedingly doubtful. 



The name Eeroe given by BROWN (Nat. Hist, of Jamaica) to the 

 animal discovered by him in the middle of the last century, is 

 borrowed from Mythology ; it is that of one of the numerous 

 daughters of Oceanus : 



Clioque et Beroe soror, Oceanitides ambo. 



VIRGIL, Georgic. Lib. iv. 341. 



Comp. on this order : RANG, Etdblissement de la Famille des Beroides et 

 description de deux genres nouveaux qui lui appartiennent ; Memoires de la 

 Soc. d'Hist. nat. de Paris, Tom. iv. 1828, pp. 166 173, PI. 19, 20. 

 MERTENS Beobachtungen und UntersucTiungen uber die ~beroeartigen Aca- 

 lepken, Mem. de I'Acad. imp. des sc. de St. Petersbourg, sc. pJiysiq. sixieme 

 s^rie, Tom. n. 1838, pp. 479 543, Taf. i. xm. (A copious extract may 

 be found in OKEN'S Isis, 1836, s. 311 321.) LESSON, Mem. sur la 

 famille des Beroides, Ann. des Sc. nat. 2 e se"rie, Tom. vi. Zool. 1836, 

 PP- 235266. 



Family V. Beroidea. (The characters of the order are those 

 of the single family.) 



A) Stomach small. 



Cestum LESUEUR. Body transverse, elongate, gelatinous, with 

 ciliated margins. 



Sp. Cestum Veneris LESUEUR Nouv. Bullet, de la soc. philom. Juin, 1813, 

 PI. v. (Recus. in OKEN'S Isis, 1817, s. 1505 1508, Tab. xn.) GUE'RIN, 

 Iconogr. Zooph. PI. 18, fig. i. (after a drawing by LAURILLARD) in the 

 Mediterranean. This girdle of Venus has the form of a band of more 

 than five feet long, and full two inches high. In the thinner inferior edge 

 is situated the oral aperture (opposite to the place assigned to it by 

 LESUEUR in the thicker superior edge). In Cestum Najadis ESCHSCH. 

 Acal. Tab. I. fig. i, from the South-Sea, near the Line, two long tentacula 

 beset with fine threads are present, which in the species from the 

 Mediterranean are often, and in Cestum Amphitrites MERTENS (1.1. Tab. i.) 

 are (always ?) wanting. 



The genus Lemniscus QUOY and GAIM. is probably founded on a detached 

 piece of Cestum. 



