MARINE POLYZOA. 37 



Zooph., places it doubtfully next to Gemellaria, he at the same 

 time says that he was more inclined then than formerly to arrange 

 it with Sertularia. He very shrewdly surmises the real nature 

 of the tobacco-pipe-like processes in comparing them with the 

 " bird's-head" processes in the Cellularia?, though wrong in sup- 

 posing that there is any analogy between them and the " some- 

 what similar organs" in Laomedea obliqua. In a paper in the 

 Transactions of the Microscopical Society (cited above), an en- 

 deavour is made to show the true nature of this Polyzoon and to 

 describe the somewhat complicated structure of the polyzoary. 



Fam. 7. CABEREAD^E. 



Polyzoary dichotomously divided into ligulate, bi-multiserial 

 branches ; on the backs of which are vibracula, or avicularia, one 

 common to several cells ; avicularia sessile. 



Cabereadae, Busk, Voy. of Rattlesn. i. 376. 

 Synopsis of Genera. 



1. Caberea. 



2. Amastigia. 



1. CABEREA. 



Cells bi-multiserial, in the latter case quincuncial. Back of 

 branches covered with large vibracula, which are placed obliquely 

 in two rows, diverging in an upward direction from the middle 

 line, where the vibracula of either side decussate with those of the 

 other. Avicularia, when present, sessile on the front of the cell. 



Caberea, Lamx. CoralL 128, 1816; Blainv. 1830; Gray, Cat. 



Brit. Had. 147. 



Selbia, Gray, Dieffenb. N. Z. ii. 292; Cat. Brit. Rad. 147. 

 Crisia (sp.), Audouin, Expl. 

 Cellaria (sp.), Lamb. Savigny, Egypt, pi. 12. 

 Cellularia (sp.), Fleming, Johnst. 



a. Operculatye. With a pedunculate operculum in front of the 



aperture. 



The remarkable feature of this genus resides in the vibracula, 

 which here appear to attain their utmost development. Each 

 vibraculum appears to belong, not to a single cell, as in Scrupo- 

 cellaria, but to be common or applied to the backs of seveinl. 

 They are more or less pyriform or long oval in shape, and the 

 two rows decussate with each other along the middle of the 

 branch, giving, in the narrower forms especially, much of the 

 aspect of an ear of barley, and in the wider of a straw plait. The 

 walls of the vibracula are usually thin and very transparent, so as 



