524 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



are not always apparent on the dorsal. The peristome may bear two small avicu- 

 laria (fig. 7). The branches are sometimes quite close together. 



The transversal section (figs. 14, 15) shows some very thick, external walls; 

 the tremopores are tubular and thin. The frontal abrasion (fig. 18) often makes 

 apparent a median axis (am) by no means analogous to that which results from 

 the union of the dorsal walls of the two lamellae of the Eschara ; it is due to the 

 prolonged wall of the zooecia that they are disposed as in figure 15 and that the 

 zoarium is cut according to axis (c, am, d). 



It is almost impossible to be successful with a longitudinal section showing 

 the spiramen because of its eccentric position. 



In a schematic one we obtain figure 16, in which it is very difficult to place 

 the operculum. However, it is necessary to remark that the examination of the 

 interior (fig. 20) reveals no corresponding frontal perforations. The zooecia 

 communicate between themselves by some very apparent septules on figure 19. 

 In thin section (fig. 17) the tubules of the tremocyst are always confused. 



Occurrence. Middle Jacksonian: Wilmington, North Carolina (very com- 

 mon) ; near Lenuds Ferry, South Carolina (very common). 



Upper Jacksonian (Ocala limestone) : Chipola Elver, east of Marianna, 

 Jackson County, Florida (rare). 



Co-types Cat. Nos. 62606, 64172, IT.S.N.M. 



Family HIPPOPODINIDAE Levinsen, 1909. 



The frontal is calcified. The ovicell is endozooecial. 



We have extended the meaning of Levinsen's definition, since we include in 

 this family all species provided with an endozooecial ovicell. Evidently, we can 

 not affirm that they all have the same larva, but the identity of the ovicell implies 

 that the larvae are at least closely related. 



The known genera of this family are listed below : 



Cheilopora Levinsen, 1909. 



Hippopodina Levinsen, 1909. 



Metrarabdotos Canu, 1914. 



Watersipora Neviani, 1895. 



There are certainly other genera which will be referred to this family. 



1. The specimens which we possess of Escharopsis sarsi Smitt, 1867, have endo- 

 zooecial ovicells ; therefore the genus Escharopsis Verrill, 1879. may belong to this 

 family. 



2. Levinsen 1 thought that Flustramorpha flabelligera Krauss, 1837, had endo- 

 zooecial ovicells; therefore the genus Flustramorpha Busk, 1884. may be maintained 

 and introduced into this family. 



3. Levinsen 2 thought that Harmeria diaphana MacGillivray, 1879, was pro- 

 vided with endozooecial ovicells ; Harmeria Norman may then belong to this family. 

 The type of the genus, Harmeria scutulata Busk, 1855, has no known ovicell. 



1 Morphological and Systematic Studies on the Cheilostomatoiis Bryozoa, p. 328. - Idem, p. 316. 



