PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 191 



cula. Length of zooecia, O.GO"'" to 0.70™™ ; breadtli, 0.50™'" to O.GO™™ ; 

 breadth of apertures, 0.12™™ to 0.15™™ ; of median pore, 0.05™™ to O.OG™™. 

 The zooecia are about twice as hxrge as those of P. ciliata. 



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



In the nearly circular form of the median pore this species approaches 

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

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

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

 the latter has a crescent-shaped pore. 



TMc genus Porellina 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 Rejytoporina, based on the 

 encrusting forms with aperture and special pore 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. Hincks has recently proposed a genus, Microporella, with P. 

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

 Dipoi'ula Hincks* seems scarcely worthy of generic separation from 

 the latter. 



Smittia Hincks (=EschareJla Smiti, non Gray). 



The genus Pscharella, as defined by Smitt, still included somcAvhat 

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

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

 ter, since it varies in the form and breadth of the siiuis, in the several 

 species now known, from an ill-defined, broad, sballow sinus, nearly as 

 in Lepralia, to a deep and narrow one, like that of Uscharina {Hippotlioa 

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

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

 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. sangui- 

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

 well referred to Escliarina {ScMzoporella Hincks), as here limited. The 

 species first described in 1853, by Stimpson, as Flustra solida {=Esckara 

 palmata Sars), and referred to Pscharella by Smitt, seems, however, 

 worthy of generic separation, on account of the chitinous fibres 

 strengthening the zoarium. It appears to belong to the genus Flusfri- 

 morpha Gray, 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 apertures. 



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

 is still room for diversity of opinion. Pscharella Gray, 1848, {non D'Or- 

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

 *Aiiiials and Magasiue of Natural History, vol. iii, p. 156, Feb., 1879. 



