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BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
Affinities . — It is not certain that the zoarium was articulated. The only 
claviform segment (fig. 18) observed contained radicular zooecia at its base; but this 
might well be considered as the base itself of the zoarium. Nei^ertheless we have 
never observed branched segments. . 
Fig. 60. — Anatomy of the subfamily Microporidae. 
A. Micropora unicifera Busk, 1884. Sketch showing anatomy of polypide, X 270. (After 
Jullien, 1888.) 
B. Micropora coriacea Esper, 1791. Transverse section through the endozooecial ovicell, 
X 40. (After Levinsen, 1909.) 
C. Sketch combining frontal (to the left) 
(After Harmer, 1902.) 
crypt, cryptocyst. 
7, intestine. 
mdg, dilator muscles of the tentacular sheath. 
mg, large retractor muscles of the polypide 
(of the sheath and of the lophophore). 
mop, opercular occlusor muscles. 
mp, parietal muscles. 
and basal (to the right) views of Micropora. 
occl, occlusor muscles of the operculum. 
oe, esophagus. 
ople, opesiule (frontal view). 
ople', opesiule (basal view). 
pli, pharynx. 
t, tentacles (10 in number). 
This fragile species is very close to Smittipora ( Vincularia ) canalifera Hage- 
now, 1851 of the Maestrichtian. from which it differs in its smaller micrometric 
measurements (Lz 0. 34 mm and not 0.44 mm.) and in its elliptical instead of 
subcircular opesium. 
