Phylum alio phor a [231 



Una, the posterior end seated in a chitinous lorica, the peristomal area broadly ex- 

 panded as two wings. 



Family Halterina Claparede and Lachmann Etudes Inf. 1: 367 (1858). Family 

 Halteriidae Claus. Halteria, subglobular, with a single whorl of long cilia; familiar in 

 infusions, recognizable by the motion of the cells, alternately revolving slowly and 

 snapping violently from place to place. 



b. Loricate, free-swimming. Suborder Tintinnoinea Kofoid and Campbell. 

 Suborder Tintinnina Hall. 



Family Tintinnodea Claparede and Lachmann Etudes Inf. 1: (1858). Family 

 Tintinnidae Claus. Peristomal membranelles elongate and ciliate, the cylindrical or 

 conical body attached in and retractile into the lorica; characteristically with two 

 macronuclei and two micronuclei. Mostly marine. Kofoid and Campbell, who mono- 

 graphed the group ( 1929) , found it possible to distinguish the natural and subordinate 

 groups entirely by the structure of the lorica. They divided the former single family 

 into twelve and recognized more than three hundred species. 



c. Laterally flattened, with a tough membrane and few cilia and membranelles. 

 Suborder Ctenostomata Kahl. Suborder Ctenostomina Hall. 



Family Ctenostomida [Ctenostomidae] Lauterborn in Zeit. wiss. Zool. 90: 665 

 (1908). Kahl (1932) monographed the group and found twenty-five species, which 

 he arranged in six genera and three families. 



d. Cylindrical, entozoic, with no ciliation except the membranelles. Suborder 

 Entodiniomorpha Reichenow. Suborder Entodiniornorphina Hall. 



Family Ophryoscolecina Stein Org. Inf. 2: 168 (1867). Family Ophryoscolecidae 

 Claus. Becker (1932) reviewed previous studies of this group, examples of which 

 were first mentioned by Gruby and Delafond, 1843. He noted 71 species, of the 

 genera Entodinium, Diplodinium, Ophryoscolex, Epidinium, etc. (the genera were 

 first named by Stein) in the domestic ox; and 52 {Didesmis, Paraisotricha, Spirodin- 

 ium, Cycloposthium, etc.) in the horse. Dogiel (1927) monographed the family, but 

 it is certain that large numbers of species remain to be discovered in wild animals, 

 oxen and others. 



The barrel-shaped cells are about 0.1-0.25 mm. long. The cytostome is anterior, 

 surrounded by the usual spiral band of membranelles; this may be broken up into 

 several partial files, and there may be belts or clusters of membranelles on other parts 

 of the body. The posterior end is drawn out into processes, one, few, or many, ob- 

 scure or prominent, horn-like or fringe-like. Internally, beside contractile vacuoles 

 and a neuromotor apparatus including a large motorium, there are characteristic 

 skeletal plates. These consist of minute cylindrical bodies imbedded in an amorphous 

 matrix, the whole staining with iodine and consisting supposedly of some polysac- 

 charide carbohydrate. 



Animals are infected by eating food contaminated with the saliva of others. The 

 ciliates may be present in the rumen in numbers from one thousand to three million 

 per cc. It has been supposed that they are symbiotic, benefitting their hosts by carry- 

 ing on useful syntheses, or perhaps merely by controlling numbers of bacteria in the 

 rumen. There is no good evidence for these ideas: the probability is, that they are 

 harmless commensals. 



e. Cylindrical or obconic, sessile, cilia of the peristomal band separate, body 

 otherwise naked. Suborder Chonotricha (Wallengren) subordo novus. 



Family Spirochonina Stein Org. Inf. 2: 168 (1867). Family Spirochonidae Grob- 



