492 MR. A. W. WATERS ON 



the two pores desciibed in the fossil Micropora articulata Waters 

 ai-e explained, the one being the avicularian and the other the 

 radicular opening. The avicularium is by the side of the aperture, 

 and the mandible is triangular. 



There are 11-12 tentacles. 



The testes extend all down the lateral wall. A very few small 

 ovaria with one to three small ovarian cells were found. 



A small ovum is found in a small sac hanging from the 

 opercular region (text-fig. 79). The sac and ovum grow until 

 ultimately the embryo nearly fills the zooecium, and now there 

 are small muscles from the opercular wall to the ovicell and 

 a strong lateral band. There is no external indication of any 

 ovicell nor of which cells contain an embryo. The embryo is 

 relatively large, with the couronne very large and distinct, and 

 the way in which the embryo grows in the pendant sac may 

 throw light upon the development of the ovum and embryo in 

 Adeonella, but no stage has been found with a sac hanging from 

 the opercular region in Adeonella. 



The present species, as T have previously indicated, is closely 

 allied to the fossil Celhdaria diplodidymoidjes Meun. & Pergens 

 from the Chalk, and both belong to the same genus *. Canu has 

 described four fossil species from the Paris Basin, but, unfor- 

 tunately, he has not given figures as well as photoglyphs. In 

 the work there are a number of magnificent photographs, 

 showing the characters most beautifully, but some of the Paris 

 authorities are making too hard and fast a line that everything 

 must be photographed. The specimens in question (pi. v. figs. 

 6-10) do not lend themselves to photography, and require either 

 figures or full description for elucidation. 



These Zanzibar specimens are so difi^erent in the younger and 

 older joints that with fossils several species might be made from 

 one colony. 



Canu t says that the genus D Iplodidymia is the Poricellaria of 

 d'Orbigny, but the description of this latter leaves recognition 

 impossible without direct comparison, and therefore Canu is quite 

 right in retaining the name Diplodidymia Reuss. 



Loc. Off Ka.tow, New Guinea, 7 fath. ; Singapore (fide White- 

 legye, in lit.). Chuaka, Zanzibar, 3 fath. (506), collected by 

 Crossland. 



Fossil. Gass, near Dax, S. France, Oligocene ; Montecchio 

 Maggiore, IST. Italy, Bartonian. 



Chlidonia cordieri Audouin. (PI. LXV. figs. 15, 16.) 



Eua-atea cordieri Aud. Descrip. de I'Egypte, Hist. nat. p. 242, 

 2nd ed. p. 74 ; Savigny's pi. xiii. fig. 3. 



Chlidonia cordieri Waters, Journ, Linn. Soc, Zool. vol. xxvi. 



* " Bryozoaires du Systfeme Montieii," Louvain, p. 3, pi. ii. fig. 3 

 t " Bryozoaires des Terrains Tertiaires des Environs du Paris," Ana. de Pal^ont. 

 t. ii.-v. p. 39 (1907). 



