338 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



us more useful to preserve it. at least provisionally, for all the species imperfectly 

 studied and classed. 



All the other species have the ovicell closed by the operculum and form a 

 heterogeneous group. 



The function of the avicularia is unknown, but it has certainly not the univer- 

 sality of the hydrostatic system. However, on many bryozoa, the avicularia 

 appear to be indispensable, for they are constant in form and position. For 

 example, the group of Schizoporella auriculata (genus Schizomavella) is orna- 

 mented by a very constant median avicularium. 



On other species the avicularia occupy a lateral or eccentric position. They 

 belong to the still poorly denned groups of Schizoporella vulgaris, including the 

 fossil forms, Eschara phymatopora Eeuss. 1869, and Lepralia schizostoma MacGil- 

 livray, 1898, of SchisoporeUa argentea with the fossil representative Schizoporella 

 terebrata Maplestone, 1901, and of Schizoporella spinifera. 



A number of Schizoporellae are absolutely deprived of avicularia; they have 

 been divided into the genera Phonicosia, Arthropoma, and Dakaria, according to 

 the special function of the rimule. 



A rather important group appears to have a little chitinized operculum. The 

 functions of this important organ are then assumed by the peristome specially devel- 

 oped; this is the curious genus Metroperiella. The group of Waters with large 

 operculum does not appear a natural one to us. 



Genus SCHIZOPODRELLA Canu and Bassler, 1917. 



1917. Schisopodrella CANU and BASSLER, Synopsis of American Early Tertiary Cheilostome 

 Bryozoa, Bulletin 96, United States National Museum, p. 40. 



The ovicell is hyperstomial. It opens above the aperture by a special opening 

 closed by a special membrane and without connection with the operculum; it 

 surmounts this aperture without inclosing it. The inferior border of the aperture 

 is somewhat concave and bears a narrow rimule. The frontal is a tremocyst 

 direct or covering a very thin olocyst finely perforated. The muscular attach- 

 ments are generally at a distance from the border of the operculum. There are 

 oral glands. 16-21 tentacles. 



Genotype. Schizopodrella (Lepralia} unicornis Johnston, 1847. 



Range. Lutetian-Recent. 



Waters in 1913 (p. 505) differentiated this genus without naming it. Schizo- 

 podrella differs from Stephanosella in the tremopores which ornament its frontal 

 and ovicell. It differs from Lacerna in the absence of areolae. 



The recent species of this genus are : 



Schizopodrella (Lepralia) unicornis Johnston, 1847. 



Schizopodrella (Schizoporella) longirofstris Hincks, 1888. 



Schizopodrella (Lepralia) errata Waters, 1879. 



Schizopodrella (Schizoporella) elmwoodiae Waters, 1900. 



Schizopodrella (Schizoporetta) nivea Busk, 1884. 



Schizopodrella (Lepralia) linearis Hassall, 1841. 



