MARGARET R. HAASE. 



definite number of cells, seventeen each. In spite of the fact that 

 Prorhynchus stagnalis has no specialized sensory tissue in the 

 form of a pair of simple eyes, Prorhynchus stagnalis is considered 

 being more highly developed in that a much larger number of 

 cells go into the formation of the pits than in both of the sensory 

 organs of Prorhynchus applanatus. 



3. The ciliated pits of Prorhynchus stagnalis are sharply 

 differentiated into three regions: transitory, sensory, and 

 glandular. 



4. There are two interesting features to the glandular cell not 

 noted in Prorhynchus applanatus: (i), the characteristic curva- 

 ture of the nucleus; and (2), the intra-cytoplasmic canaliculi. 



5. The ciliated pits of Prorhynchus stagnalis possess a definite 

 musculature, attached to both their mesial and lateral walls. 



LITERATURE. 

 Benham, W. B. 



'01 A Treatise on Zoology, E. Ray Lankester, Part IV. Platyhelmia, etc. 



London. 

 Dahlgren, Ulric, and Kepner, Wm. A. 



'08 A Text-Book of the Principles of Animal Histology, pp. 258-268. The 



Olfactory and Gustatory Nerve Tissues. 

 Graff, L. von. 



'09 Die Siisswasserfauna Deutschlands. Heft 19. Jena. 



'13 Das Tierreich, 35. Leiferung. Turbellaria II. Rhabdocoelida. Berlin. 

 Kepner, Wm. A., and Taliaferro, W. H. 



'12 Sensory Epithelium of Pharynx and Ciliated pits of Microstoma caudatum. 



BIOL. BULL., Vol. XXIII. 

 Kepner, Wm. A., and Taliaferro, W. H. 



'16 Organs of Special Sense of Prorhynchus applanatus Kennel. Journal of 

 Morphology, Vol. XXVII. 



