212 HYATT, 



three last named genera. Although the polypides of the 

 Phylactolaemata never display any marks of fissiparity, the 

 coenoecia are multiplied by division. 1 have seen thelobi- 

 form branches of old colonies of Pectinatella divided from 

 the coenoecial trunk by constrictions, which, gradually deep- 

 ening, finally separated them from the latter. The form, 

 the thickness of the ectocyst, and the vast number of coe- 

 noecia upon every mass, indicate, that this selfmultiplica- 

 tive mode of propagation is of frequent occurrence among 

 the adults. 



Prof. Allman has observed similar phenomena in Cris- 

 tatella and Lophopus, showing it to be common to all the 

 genera having the thickened gelatinous ectocyst. It ap- 

 pears probable, that this method of multiplying the colonies 

 would also take place in Fredericella and the Plumatellse, 

 if it were not for the toughness of the ectocyst. The par- 

 tial divisions continually occuring in the branches of these 

 genera and, apparently, restrained only by the stiffness of 

 the ectocyst from becoming effective and severing the 

 coenoecia, wherever they occur, into separate parts, are the 

 homologues of the permanent septa between the cells of 

 Paludicella and of the lateral partitions in the marine 

 Polyzoa. This homology was suggested to me in observ- 

 ing the readiness with which the lobes of Pectinatella were 

 cut off; the constrictions occuring irregularly, sometimes 

 isolating a whole branch, sometimes only a few cells. If 

 the ectocyst was pergameneous in this genus the constric- 

 tions would either not take place at all, or form scattered 

 partitions, as in Fredericella and Plumatella. Thus the 

 same function that produces a constant anatomical char- 

 acter in Paludicella, Fredericella, and Plumatella, would 

 seem to be the effective cause of the selfmultiplication of 

 the ccenoscia in Lophopus, Pectinatella and Cristatella. 



Prof. Allman divides the mode of reproduction by buds 

 into two, "non sexual reproduction by gemma?, which at 

 once proceed to the full term of their destined develop- 

 ment," and "by statoblasts or gemmae in which the develop- 

 mental activity remains for a period latent."* 



The statoblasts bud from the funiculus, a cord like pro- 



*Frcsh-water Polyzoa. p. 41. 



