BRYOZOA FROM ZANZIBAR. 481 



There ore about 16 tentacles. 



The vibi'aciilum of Cancla retiformis is of the same chai-acter as 

 that of Scrivpocellaria, in which genus some of the vibiacular 

 chambers extend beyond the median line of the zoarium, though 

 not quite as much so as in the two species of Cauda ; also the 

 vibraculum of Caherea has the same general character. 



I have several times maintained* that there are material dif- 

 ferences between avicularia and vibi-acula, but that the length of 

 the mandible or seta is of no importance in indicating which they 

 are. The distinctions are in the chamber and the basal part of 

 the chitinous organs. While the mandibles of avicularia are 

 symmetrical and have the closing muscles attached by tone or 

 two long tendons, the base of asymmetrical seta of the vibia.cula 

 is very complicated with a large number of curiously shaped pro- 

 tuberances, to some of which the muscles are attached by a 

 fascia, but without any long tendon, so that instead of there 

 being two main mviscles, there are more attached by a short band 

 to various parts of the base of the seta. The vibracular base is 

 very small, so that it is difficult to follow this complicated 

 mechanism ; the reason for this complication is found in the seta 

 being movable in all directions, whereas the mandibles of the 

 avicularia only move in one. The mandibles all have a straight 

 proximal edge, but this is not the case in the seta ; further, the 

 avicularian mandible works from this straight base either against 

 the calcareous bar, or, in case this is not complete, then fi-om two 

 teeth. The universal movement could not take place with a 

 cross-bar, and none has been found, nor must we ever expect to 

 find one in vibracula. The vibracular chambers of this group 

 are different from those of Ciipulariat, etc., in which the vibracular 

 chamber takes the place of a zooecium. 



Loc. Florida, 68 & 270 fath. ; Loyalty Islands (Ph.); Galle, 

 deep water (Th.); Amirante, 23-29 fath., Saya de Malha, 55 fath., 

 Seychelles, 39 fath., Cargados, 30 fath. {Thornely). Wasin. Biit. 

 East Africa, 10 fath. (501); Prison Island, Zanzibar Channel 

 (505), 8 fath., Ras Osowamembe, Zanzibar Channel, 10 fath. (504), 

 collected by Crossland. 



Catenaria lafontii Audouin. , 



Waters, " Rep. Sudanese Red Sea,'' p. 131. 



Near the distal end there are small ovaria with two ovarian 

 cells. 



Log. Wasin, Brit. East Africa, 10 fath. (501); Prison Island, 

 8 fath. ; Chuaka, 2 fath. (508), 3 fath. (526) ; Meweni Bay, 6 fath.' 

 (510); Zanzibar town, shore (527). 



* R(5sultats du Voyage du S.Y. Belgica, " Biyozoa," p. 27. Zool. Cliall. Exp 

 vol. Ixxix. p. 22, pi. i. fig. 12. 

 f See page 529. 

 X Veiy minute glands occur in the vibracula of Cupularia. 



