TTJBULARIA INDIVISA. 115 



sent, and the young, on issuing from the ovisac, has 

 already assumed the polypite form. A verticil of long 

 arms surrounds the base of the proboscis ; and the oral 

 series is either present in a rudimentary condition or 

 subsequently developed (Plate XX. fig. b, b) . The embryo 

 walks about by means of its arms, like a cuttlefish, with 

 its head downwards*. After a time it attaches itself by 

 its base, and the stem is gradually developed. 



We meet with a similar mode of reproduction in a mem- 

 ber of the genus Coryne (C. VanBenedenii] and also in My- 

 riothela. 



The polypites of Tubularia, at least when kept in capti- 

 vity, are shed at short intervals, but are soon renewed. 

 The prolific pulp gives origin to a succession of genera- 

 tions ; and the birth of each is registered by the formation 

 of a ring on the polypary. 



1. T. INDIVISA, Linnaeus. 



"TUBULAR CORALLINE, LIKE OATEN PIPES," Ellis, Corall. 31, t. xvi. fig. 6. 

 TITBULARIA INDIVISA, Linn. Syst. 1301 ; Lamk. An. s. Vert. (2nd ed.) ii. 125 ; 



Lamx. Exp. Meth. 17 ; Daly ell, Rem. An. Scotl. i. 2, pi. i. ii. 



iii. & iv. ; Lister, Phil. Trans. 1834, 366, pi. viii. fig. 1 ; 



Johnst. B. Z. 48, pi. iii. figs. 1, 2 ; "Mummery, Q. J. Microscop. 



Sc. for 1853, 28; T. S. Wright, Ed. N. P. Journ. (N. S.) for 



Jan. 1858, 113, pi. iii. figs. 2, 3; Allman, Ann.N. H, for July 



1859. 



CALAMARIS, Pall. Blench. 81 ; Ehrcnb. Corall. roth. Meer. 71. 



(?) TUBVLARIA OIGANTEA, Lamx. Expos. 17, t. Ixviii. fig. 5. 



Plate XX. 

 STEMS clustered, simple, erect, without cumulation, narrowed 



* Van Beneden's statement respecting the young of T. coronata, "elle 

 n'a aucun moyen de locomotion," is incorrect. The tentacles are employed 

 as feet. They are also used as oars, by means of which it moves freely 

 through the water ; and in more than one case probably the floating Tubu- 

 larian embryo lias been taken for a new generic form. 



i 2 



