PROTOZOA. 15 



has a terminal mouth. Fission seems to be the only mode of ',.. 

 reproduction. These organisms sometimes occur in colonies. { . ., 

 Lophomonas is found in the intestines of Periplaneta orientalis. 



Euglence occur in green masses in our ponds in the spring. 

 Flagellated organisms are sometimes found in the blood. Some 

 are scarcely distinguishable from the spores of certain Algae. 

 Peridinium is phosphorescent. 



Noctiluca, forming the class Myxocystodea of Carus, is a glo- 

 bular organism furnished with a short stalk, a mouth, and a 

 digestive cavity ; in temperate climates it is the principal cause of 

 the luminosity of the sea. According to Allman, the special seat 

 of the phosphorescence is the peripheral layer of protoplasm 

 which lines the exterior structureless membrane. 



Peridiniidce. Astadidce. Monadidte. 



Peridinium. Euglena. Monas. 



Ceratium. Astasia. Cercomonas. 



Lophomonas. 

 Noctiluca. 



Order in. SUCTORIA. 



AciNETA-forms. POLYSTOMA. TENTACULIFERA. 



Body stalked, provided with radiating retractile tubes, having 

 at the extremity a disk-shaped mouth, acting as a sucker. No 

 cilia in the adult. 



The prey is seized by these tubes, and the nutrient matter is 

 then imbibed by the suckers. They have no definite mouth. 

 There is only one family : 



Acinetidce. 



Acineta. 



Podophrya. 



Ophryodendron. 



A remarkable group of Infusoria of very minute size, distin- 

 guished by the presence of a hyaline " wineglass-shaped struc- 

 ture " at the anterior extremity, from which the flagellum takes 

 its origin, has been investigated by J. Clark, and more recently 

 by Saville Kent and Biitschli. They have been called " Flagel- 

 late " or " Collar-bearing Monads." The principal genera are 

 Codosiga, Salpingwca, Codomoeca, Dinobryon, and Antophysa. 



