ESCHAROIDES QUINCUNCIALIS. 339 



EscHAROiDEs QUINCUNCIALIS, Noi'man. 



Plate XV. fig. 7. 



EscHARA QUINCUNCIALIS, Novman, Hebridean Polyz., Rep. Brit. Assoc, for 

 1866 (1867), 204; Quart. Journ. Micr. Sc. (n. s.) viii. 10, 

 pi. vii. figs. 1-3. 



Zoariiim cylindrical, smooth, polished. Zocecia in linear 

 series, disposed quincuncially round an imaginary axis, 

 almost confluent, flat or slightly depressed below, the 

 oral region mammseform ; orifice (adult) rounded above, 

 usually with a sinus, placed towards one side on its 

 lower margin, and a small and inconspicuous avicularium 

 close to it ; the peristome raised and thickened. Ooscia 

 rounded, subimmersed, with an arched space in front, 

 filled in by less highly calcified material, and some- 

 times perforated, closely united to the raised peristome, 

 and forming with it elongated mamillary risings on 

 the upper portion of the cell. 



Locality. Dredged in deep water in the Minch (A. 



M. N.). 



The specific character is founded on the fragment, 

 " not more than a quarter of an inch long," which was 

 obtained in the Hebrides by Messrs. Jeff'reys and Nor- 

 man. So minute a specimen does not afford the means of 

 studying the various stages in the development of the 

 zooecium ; and the diagnosis must be accepted subject to 

 any corrections which a more thorough study of the 

 species may supply. An examination of the few marginal 

 cells available for the purpose shows that, in the earlier 

 stages of growth, the minute avicularium is borne on a 

 short rostriform elevation, placed a little towards one side 

 of the primary aperture. At this point the raised and 

 thickened peristome, which is so marked a characteristic 

 of the adult, is not formed ; when developed it seems to 



z2 



