NORTH AMERICAN EARLY TERTIARY BRYOZOA. 455 



FIG. 130. Anatomy of the Smittinidae Levinsen, 1909. 



A, B. Porella lews Fleming, 1828. A. Free larva, X 75. B. Ancestrula. (A, B after 

 Barrels, 1877.) 



ca, calotte (terminal bud) ; ph, pharynx; 



CD, digestive cavity ; si, furrow ; 



ce, portion of the body between the two g, disseminated fat globules seen in the stages 



branches of the stomach; following fixation; 



est, stomach ; pvl, rudiment of the polypide ; 



mi, aboral mesoderm ; sp, spines of cell. 



ms, oral mesoderm ; 



C-E. Mucronella peachi Johnston, 1848. C, D. Ciliated embryoes. E. Zooecial anatomy. 

 The place of the rectum does not appear to be exact. Letters as in figure G. (C-E after 

 Smitt, 1S65.) 



F, G. Porella cervicornis Pallas, 1766. F. Polypide with the tentacles arranged in the 

 tentacular sheath. G. The same with the tentacles extended. (F, G after Milne-Edwards, 

 1838.) 



bg, edge of the tentacular sheath ; /, filiform appendages of alimentary canal ; 



coec, caecum of the stomach ; ph, pharynx ; 



est, stomach ; r, rectum ; 



mr, retractor muscles of the polypide ; t, tentacles. 



H. Smittina trlspinosa Johnston, 1838, var. arborea Levinsen, 1886. The compensatrix (cs) 

 is attached to the operculum (op). Its orifice is overhung by a median lobe of the frontal 

 shield. The condyles (cond) are at a much deeper level and are long recurved denticles, which 

 are crossed by the submarginal lateral sclerites (scl) of the operculum. The author has not 

 figured the parietal muscles. (After Harmer, 1902.) 



I. Smittina tripora Waters, 1904. Section showing aperture with operculum, and below it 

 the avicularian glands, with the mandible above the glands; X 85. (After Waters, 1904.) 



J. Smittina protecta Thornely, 1907. Polypide removed from the zooecium, showing the 

 small oral (vaginal of Calvet) glands (</), the diaphragm (d), and the tentacles (t), X 85. 

 (After Waters, 1908.) 



K. Smittina ophidiana Waters, 1878. Distal extremity showing the oral glands, X 85. 

 (After Waters, 1892.) 



L. Kmitiina trispinosa Johnston, 1838. Distal end, showing oral glands, X 85. (After 

 Waters, 1892.) 



M, N. Porella acutirostris Smitt, 1S67. M. Piece mounted in balsam, showing the avicu 

 larian glands through the seniitransparent shell, X 50. N. Section of avicularian gland, X 

 250. (M, N after Waters, 1900.) 



O. Sketch of several zooecia, showing terminology. 



