24)4 MK. A. W. WATERS OJN 



18, pi. 3. figs. 20, 21 ; Ortmann, " Invertebrate Fossils from Patagonia," 

 Amer. Journ. of Sci. ser. 4, vol. x. p. 368 (1890). 



Eschara gigantea, Busk, Brit. Mus. Cat. p. 91, pi. 119. fig. 3; Jiillien, 

 Mission Scientifique du Cap Horn, p. 77, pi. 6, figs. 5, 6. 



Aspidostoma crasswm, Hincks, Ann. Mag. Nat. Hist. ser. 6, vol. vii. 

 p. 160, pi. 10. fig. 6 (1881): MacGillivray, Tert. Polyzoa of Victoria, 

 p. 102, pi. 13. fig. 12. 



Steganoporella patula, Waters, Quart. Journ. Gaol. Soc. vol. xxxvii. 

 p. 265, pi. 9. fig. 31 (1882). 



Micropora cavata, Waters, Quart. Journ. Geol. Soc. vol. xxxix. p. 435. 



Specimens from Cape Horn are sometimes broadly foliaceous, 

 sometimes reticulate with the fenestrse large, attaining to 20 mm. 

 by 10 mm.; all seem to be bilaminate. 



The operculum forma a thick sac, and has a projecting knob 

 at each proximal corner (as figured in my 'Challenger' 8upp. 

 Bep. pi. iii. fig. 21), to which are attached muscles. At the 

 proximal edge of the oral aperture there is a lamina rising at 

 right ansfles to the operculum, and proximally to the lamina there 

 is a hollow space into which the "elongate callosity" of Hincks 

 may project as a mucro. A hollow space of this kind occurs in 

 several genera of Bryozoa, and the zooecium is contracted thereby. 

 The loop-shaped openings at each side are for the knobs of the 

 opercula, and are in no way similar to the opesiulea oE Micropora, 

 &c. through which a muscle passes. 



The zooecia are connected distally through long tubes, wliich 

 frequently have a dividing disk in the middle (PI. 29. fig. 2), and 

 sometimes the tubes bifurcate. The number of these tubes is 

 usually 8, representing as many rosette-plates, and there are 

 about 6-9 lateral rosette-plates *. 



* The name " origella " given by JuUieu " a tons les bourgeons de Tendocyste, 

 depuis I'etat rudimentaire jusqu'au moment ou le boui'geon devient un zoide 

 quelconque" (Miss. Scient. du Cap Horn, p. 12), has never seemerl to me to be 

 required. There are growing and vital tissues in different forms, from which 

 soiuetimes new zooeoia are formed, or which pass through the pore-tubes to the 

 surface. The growing tissue, when new zooecia are being formed, is, from time 

 to time, separated by disks at intervals and in different ways, according to the 

 species. These are the rosette-plates, or sepfcules of Jullien, and their form 

 and other peculiarities furnish useful characters. 



Jullien (' Bryozoaires provenant des campagnes de I'Hirondelle,' Jullien & 

 Calvet, p. 18) says that I have stated the rosette-plates to be the equivalent 

 of his " ox-igelles." This is a misunderstanding of what I said, which was that 

 the rosette-plates represent the origella, by showing to us, not only in living, but 

 also in fossil and dried specimens, the position of the origella. The rosette- 



