RHAJJDOPLEURID^G. 577 



Subclass PTEROBRANCIIIA, E. Ray Lankester. 



ASPIOOPIIORA, Alliuau, Journ. Liun. Soc. Zool. nv. 1879. 



Order PO DO STO MAT A, Lankester. 

 Foot large, discoid, overhanging the mouth. 



Family Rhabdopleuridae. 



ZOARIUM a chitinous, adherent tube, divided by septa into 

 compartments, from which erect tubular cells rise, in 

 which the polypides are lodged ; the whole of the ad- 

 herent portions traversed by a chitinous cylindrical 

 rod, to which the polypides are attached by means of a 

 flexible cord; endocyst not differentiated, and the pofy- 

 pide consequently unattached to its cell ; retractor and 

 other muscles absent ; a large, shield-like organ (foot) 

 placed near the mouth ; the young (bud) furnished with 

 two valve-like fleshy plates. 



Genus RHABDOPLEUEA, Allman. 



Der. From pdfidos, rod, and irXevpd, side. 



RHABDOPLEURA, Allman (1867). 

 HALILOPHUS, M. Sara (1868)*. 



The only genus. 



OF this remarkable form, which constitutes the type of 



* ' Foraatte Benuerkninger om det djriske Lira Uclbredning i Havets 

 Dybder,' p. 1'J 



2p 



