[Vol. XXII, 1921.] A. Robertson: Report on Bryozoa. 41 



do the nutritive zocecia, and indeed is a transformed nutritive 

 zooecium. It also consists of two parts, a much enlarged zooecium 

 proper and a basal prolongation (Fig. 3, D). The zooecium 

 proper, again, consists of two parts. These may be distinguished 

 liy a dit^erence in the texture of the wall, the lower half being 

 membranous, the upper half being thickened and strengthened by 

 delicate calcareous plates {jcr.zoc). The calcareous wall of the 

 upper half is bulging and rounded and obviously forms a brood 

 sac or oceciuni {oe). The dorsal and ventral walls of this zooecium 

 unite distally atid are bounded by broadly rounded chitinous bars, 

 one forming the distal edge of the dorsal wall, the other forming 

 the distal edge of the ventral wall, the whole closing the mouth of 

 the ooecium through which the developed embryo {emb.) or larva 

 eventually escapes. That the chitinous rim of the ventral wall is 

 homologous with the operculum of the nutritive zooecia is obvious 

 when the muscular attachment of each is studied. The chitinous 

 opercula possess a rather broad expansion at each end to which 

 the opercular muscles are fastened. The chitinous rim of the 

 ooecium possesses a similar expansion at each end to which muscle 

 fibres are attached, and whose action presumably serves to open 

 the ooecium. Conclusive proof that the fertile zooecium is a 

 transformed nutritive zooecium is afforded by the presence within 

 the fertile zooecium of the degenerating remains of a polypide 

 (de. poly.) and of parietal muscles {de. miis.). Lying above these 

 is the large opaque body of the embryo suspended in a membran- 

 ous sheath (sh.) and only partially enclosed by the calcareous 

 wall of the ovicell. Traces of reproductive elements were found 

 in a few zooecia (B, re. ele.), and in each case these resemble 

 testis rather than ovary. In the zooecium adjoining the ooecium, 

 what is regarded as testis is also found and it is perhaps signi- 

 ficant that similar tissue extends into the basal prolongation of 

 this zooecium (1 re. ele.). In no case has undoubted ovary been 

 apparent. 



Obtained at station 193, Arabian Sea, 72°28'45" E. I5°ii' N., 

 dredged at 931 fathoms. 



This interesting specimen was obtained at a depth of 931 

 fathoms or from a depth of over a mile and is therefore to be 

 regarded as an abyssal form. Considerable difficulty has been 

 encountered in the attempt to identify it because, while it possesses 

 features undoubtedly allying it with. Kinctoskias , it possesses others 

 which differ markedly from any known species of that interesting 

 genus and which relate it to another family, viz. the Cellulariidis. 



It is aUied to Kindoskias by its unique muscular organ 

 coupled with the possession of articulated avicularia, and b}' its 

 abyssal habitat. It is allied to the Cellularians by the possession 

 of sessile avicularia and by the structure of its peduncle, while the 

 unique structure of the ooecium is unlike that of any Cheilostoma- 

 tous ovicell known to the writer save one, that of Cellularia cirrata, 

 Busk (1884), to which the species under consideration is related 

 if not identical. 



