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BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
pores. There are two pairs of lateral dietellae and a distal dietella. The ovdcell is 
hvperstomial and is always closed by the operculum. The avicularia are always 
H *25 
Fig. 82. — Genus Membraniporella Smitt, ]S73. 
A. Membraniporella distans MacGillivray, 1885. A. Zooeciura, X 55, showing terminology. 
(After Levinsen, 1909.) 
B-K. Membraniporella nitida Johnston, 183S. B. Larva, oral face, X 75. C. Aboral view 
of larva, X75. D. Free larva seen in profile, X 100. (B-D after Barrois, 1877.) 
C. D., digestive cavity. o, mouth of the gastrula. 
ce, obscure portion of the cavity of the body Ph, pharynx, 
included between the two branches of the rv, border of the terminal bud. 
stomach. si, furrow separating the terminal bud and the 
mi, aboral mesoderm. lower portion of the aboral face. 
ms, oral mesoderm (labial). 
E. Outline showing the structure of the cell, X 50. (After Hindis, 1880.) 
F, G, H. Various forms of this species. I. Ancestrula. (F-I after Hindis, 1880. ) J. Mandihle, 
X 250. K. Operculum, X 85, showing it continuous with the membrane (opercular valve). 
(J. K after Waters, 1899.) 
dependent. The aperture is closed by an opercular valve. The larva is that of the 
Escharines ( Ascophora ) . 
Genotype. — Membraniporella ( Lepralia ) nitida Johnston, 1838. 
Range. — Cenomanian-Recent. 
