76 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.61. 



The longitudinal sections are quite variable; the two which we 

 publish are not exactly similar to those of Pergens ; they differ from 

 them in the number of mesopores, the thickness of the lamellar epi- 

 theca, and in the form of the vacuoles often transformed into nema- 

 topores. The mesopores are more or less long and numerous, but 

 their walls are always quite thick. The dorsal nematopores of Per- 

 gen's figure are transformed in our sections into veritable rectilinear 

 or curved vacuoles perforating the epitheca. The gemmation is not 

 exactly dorsal as it sometimes occurs by bifurcation at all heights 

 but in a neighboring plane of the zoarial axis. The orientation of 

 the tubes is the cause of this appearance. It is in reality a peripheral 

 gemmation, oriented and symmetrical. 



The transverse section shows the tubes a little smaller in the vicin- 

 ity of the dorsal. These tubes are nematopores which become vacu- 

 oles. The vacuoles are quite small, much scattered. 



The meridian section shows the habitual losenge-shaped areas ob- 

 served on the basal lamella of species with dorsal gemmation. We 

 can not explain the presence of the pointed partition at the middle 

 of many of the losenge-shaped areas. 



Occun^ence. — Cretaceous (Coniacian) : Villedieu and Lisle (Loir- 

 et-Cher), Tours (Indre-et-Loire), and Les Phelippeaux (Charente), 

 France. 



Plesioty pes. —Cfinu collection and Cat. No. 68994, U.S.N.M. 



SEMICYTIS FENESTRATA D'Orbigny. 1854. 



Plate 26, figs. i>-7. 



1909. Homoeosolen fencstrata Gregory, Catalogue Fossil Bryozoa in British 

 Museum, Cretaceous, p. 93, pi. 2, figs. 9, 10; pi. 3, figs. 5, 6 (Bibliog- 

 raphy, geological distribution). 



Affinities. — D'Orbigny's figure representing the cellular face is not 

 exact; we give a new photograph of a specimen coming from the 

 same locality as D'Orbigny's type (Les Roches). 



The difference from Semic^jtis dispaHlis is easy to see, namely, its 

 much smaller zoarial dimensions and the very special form of the 

 orifices of the vacuoles everywhere much more scattered and much 

 less numerous. 



Occurrence.— Cv&i2iCQ0ws (Turonian) : St. Calais and Connerre 

 (Sarthe) and Luynes (Loir-et-Cher), France. 



Cretaceous (Coniacian) : Villedieu and Les Eoches (Loir-et-Cher), 

 France, and Chatham, England. 



Plesiotypes.—Cami collection and Cat. No. 68995, U.S.N.M. 



