PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 191 



cula. Lcugtli of zooecia, 0.60'^'" to 0.70'"°^ ; breadth, 0.50°"" to 0.60°i"^ ; 

 brciKlth of apertures, 0.12""« to 0.15°"" ; of median pore, 0.05""" to 0.06"^'". 

 The zo(E('ia are about twice as hirge as those of I*, ciliata. 



Casco Bay, Maine (U. S. Fish Commission, 1873). 



In the nearly circuhir form of tlie median pore this species approaches 

 the genus Poriiia, as restricted by Smitt (Florida Bryozoa); but in all 

 other respects, except size, it agrees so closely with P. ciliata, made the 

 type of PorelHna by Smitt, as to forbid a generic, separation, although 

 the latter has a crescent- shaped pore. 



The genus PorelUna was, however, originally established by D'Or- 

 bigny for erect fossil species, having the surface foveolated. In his sys- 

 tem, the present species would belong to Peptoporina, based on the 

 encrusting forms with aperture and special i)ore as in Porina. Perhaps 

 it may be desirable to separate generically the species having the hemi- 

 spherical apertures, median ciliated pore, and sublateral avicularium, 

 as in this species and P. ciliata , whatever be their mode of growth. 



Mr. Hiucks has recently proposed a genus, Microporella, with P. 

 ciliata as type, which might also, if adopted, include the present species. 

 Dipornla Hincks* seems scarcely worthy of generic separation from 

 the latter. 



Sniittia Hincks (=:EschareUaf^mitt, hoh Gray). 



The genus JEJscharella, as defined by Smitt, still included somewhat 

 heterogeneous species. The form of the zooecial aperture, chiefly relied 

 upon by both Smitt and Hincks, proves to be a rather iudefiuite charac- 

 tei', since it varies in the form and breadth of the sinus, in the several 

 S]iecie8 now known, fi'om an ill-defined, broad, shallow sinus, nearly as 

 in Lepralia, to a deep and narrow one, like that of Encliarina [Hippotlioa 

 Smitt). It would appear best, therefore, to combine, with the form of 

 the aperture, the presence of a median avicularium in front of tlie 

 sinus, or within its margin. The mere form of growth, presence or ab- 

 sence of pores in the zocecia and ocecia, are of no importance generically, 

 as Smitt has well shown. This restriction would exclude E. mngni- 

 nea Sm., U. Jacotini Sm., and some other species, most of which can be 

 well referred to Escharina {Schisoporella Hincks), as here limited. The 

 species first described in 1853, by Stimpson, as Flustra soUda {=Eschara 

 palmata Sars), and referred to Escharella by Smitt, seems, liowever, 

 worthy of generic separation, on account of the chitinous fibres 

 strengthening the zoarium. It appears to belong to the gi^nis Flustri- 

 inorpha tiray, so far as can be determined by his description, in which 

 the position of the avicularia is not mentioned, nor even the exact form 

 of the zocEcial a])ertures. 



As to the correct name for this natural and important genus, there 

 is still room for diversity of opinion. Escharella (Iray, 1848, {7ion D'Or- 

 bigny), certainly ought not to have been restricted to this division, for 

 *Aiiuals ami Magazine of Natural History, vol. iii, p. 156, Feb., 1879. 



