120 ON THE STRUCTURE OF PROTOPHRYA OVICOLA. 



character, since it is known to occur in but a single other species of the family, Ano- 

 plophrya branchiarura. Its presence in Protophrya ovicola is determined with some 

 difficulty, and a re-examination of other species with the best conditions of magni- 

 fication and illumination may extend its occurrence. Pending such an examina- 

 tion, it seems best to leave the matter of its absence in other members of the family 

 an open question. The resemblance of Protophrya to such primitive types as Holo- 

 phrya and Prorodon, the simplest forms of Holotricha, is evident. Its specialization 

 lies in the fine ciliation, the marginal zone of cilia, and the adaptive form of the 

 animal. On account of its primitive characters I place it as the lowest genus in the 

 family and have named it accordingly. 



V. BIBLIOGRAPHY. 



Foettinger, A. 



'81. Recherches sur quelques infusiores nouveaux, parasites des C6phalopodes. Arch, de Biol., torn. 2. 



pp. 344-378, pis. 19-22. 

 Quennerstedt, A. 



'67. Bidrag till Sveriges Infusorie-fauna. Acta Univ. Lundensis, for 1867, torn. 4, no. 7, 48 pp., 2 tab. 

 Schewiakoff, W. T. 



'96. [Organization and Classification of the Infusoria Aspirotricha (Holotricha auctorum).] Mem. Acad. 



Imp. Sci. St. Petersbourg, ser. 8, vol. 4, no. 1, ix+395 + 13 pp., 7 pis. [Russian.] 

 Schweier, A. W. 



: 00. [The parasitic ciliate Infusoria (endoparasites).] Trav. Soc. Imp. Nat. St. Petersbourg, Sect. Zool., 



vol. 29, pp. 1-135, 2 pis. [Russian.] 

 Vaullegeard, A. 



:01. Etude expe'rimentale et critique sur 1'action des Helminthes: I. Cestodes et Ne'matodes. Bull. Soc. 

 Linn. Normandie, ser. 5, vol. 4, pp. 84-142. 



EXPLANATION OF PLATE VIII. 



ABBREVIATIONS. 



can. eff. Efferent canal. pell. Pellicula. 



cil. Cilia. pi. ctx. Cortical plasma. 



ec'pl. Ectoplasm. po. exc. Excretory pore. 



en'pl. Entoplasm. st. alv. Alveolar layer. 



mak'nl. Macronucleus. vac. co'tr. Contractile vacuole. 



mik'nl. Micronucleus. 



PLATE VIII. 

 All drawings, with the exception of Figure 3, were based on outlines made with an Abbe camera lucida. 



PROTOPHRYA OVICOLA SP. NOV. 

 Fig. 1. Dorsal view of the whole animal; Flemming's chrom-osmic-acetic ; Benda's iron-hsematoxylin. Leitz 



homog. imm. apoch., Oc. 4. XllOO. 

 Fig. 2. The same seen from left side. XllOO. 



Fig. 3. Egg of Littorina rudis with Protophrya! upon its surface. X75. 

 Fig. 4. Marginal zone of Protophrya showing finer structure of ectoplasm and entoplasm. Same preparation as 



Fig. 1. Leitz homog. imm. apoch., Oc. 18. X3300. 

 Fig. 5. Nuclei of Protophrya; Flemming's chrom-osmic-acetic, followed by 5% bicarbonate of soda for 24 hrs.; 



Ranvier's picro-carmine. Leitz homog. imm. apoch. X1650. 



Fig. 6. Dorsal view of Protophrya showing contractile vacuole and excretory canal. X 500. 

 Fig. 7. Dorsal view of Protophrya showing trefoil stage of contractile vacuole. X500. 



