ON BUDDING IN POLYZOA. 553 



There is, however, a certain amount of direct evidence that 

 a portion of the bud is derived either from an invagination or 

 from a proliferation from the outer layer of the endocyst — in 

 other words, from the epiblast of the parent organism (see PI. 

 XXXVIII, fig. 23, &c.). 



Every one will agree that the bud contains mesoblastic 

 elements directly derived from the parent. 



Assutning, then, that the digestive tissue of the bud is 

 derived from the funiculus of the parent, a new construction 

 must be put upon this important organ of the Polyzoa, neces- 

 sitating a hypoblastic origin for a part at least of this much 

 discussed tissue. I would venture to suggest that, at all events 

 in the Gymnoltemata, a portion of the cord is indirectly 

 derived from the archenteron of the embryo which initiated 

 the colony. This derivative may be plasmodic rather than 

 cellular, and probably is more or less clothed with degenerate 

 mesoblast. If subsequent investigations can demonstrate this, 

 then the anomalous character of Polyzoan gemmation will be 

 taken away, and the phenomenon reduced to a more normal 

 method. 



Whatever value the suggestions just put forth may possess, 

 this paper will at least indicate the lines upon which this 

 question must be approached in the future. 



Bibliography. 

 General. 



(1) T. HiNCKs. — "A History of the British Marine Polyzoa." London, Van 



Voorst, 1880. 

 (1*) J, Barkois. — "Recherches sur remb. des Bryozoaires," Lille, 1877. 



Eutoprocta. 



(2) J. Reid. — "On the Anatomy and Physiology of some Zoophytes," "Ann. 



and Mag. Nat. Hist.,' vol. xvi, 1845. 



(3) B. Uljanin. — " Zur Anatomie u. Eutwickl. der Pedicelliua," No. 2, 



'Bull. Soc. Imp. des Natural,' Moscow, 1870. 



(4) H. NiTSCHE. — "Beitragezur Keuntniss der Bryozoen," ''Ueber den Bau 



u. d. Kiiospung V. Loxusoma Kefersteinii," ' Zeil. f. Wiss. Zool.,' Bd. 

 XXV, Suppl. Bd., p. 361, 1875. 



