950 PROTOZOA AND OTHER ANIMALS 



A more or less marked concavity is present on one side near the 

 anterior end of many species of the Astomata mentioned above. This 

 concavity, often supported by skeletal fibrils, may fit easily on the convex 

 surface of the intestinal folds. It is not differentiated as a true sucker, 

 however. The projecting spines and hooks of the skeletal apparatus of 

 many forms serve definitely for attachment. These are adaptations to the 

 requirements of the habitat, but it is a question whether the skeletal 

 apparatus as a whole can be considered to be strictly a fixation apparatus. 



In the Astomata of the family Haptophryidae, there is a true sucker. 

 If there is a systematic unity in the family, the wide separation of the 

 two groups of hosts, Turbellaria and Amphibia, is noteworthy. The 

 species that have spicules, Lachmannella without and Steinella with an 

 anterior acetabulum-like concavity, occur only in various Turbellaria, 

 and since there are no complete and modern descriptions, comparison 

 with other Haptophryidae is difficult to make. The several species of 

 Haptophrya are better known, especially H. michiganenns Woodhead, 

 1928, as described by Bush (1933, 1934). H. gigantea has been found 

 in certain European and Algerian frogs and toads; and H. mkhiganensh 

 in several American salamanders and one frog. Rankin (1937) reported 

 the latter species from 5 of 19 species of North Carolina salamanders, 

 in incidence of 6.3-21.4 percent; and Hazard (1937) found it once in 

 Plethodon cinereus in Ohio, which species Rankin had reported nega- 

 tive. Hazard also found the ciliate in 20 percent of Rana syhatica in 

 Ohio. There may be some difi^erence in infection in the same host species 

 in dififerent geographic regions. Cepede (1910) noted that R. esculent a 

 harbors H. gigantea in Algeria, but lacks it in Northern France. Rankin 

 found what he considered to be H. gigantea, together with H. michi- 

 ganensis, in a few of the many Plethodon glutinosus studied. Meyer 

 (1938) reported H. virginiensis, a new species, in R. palustris. 



The occurrence in a turbellarian of a species often put into the same 

 genus, Haptophrya, is of interest from the standpoint of host-specificity. 

 The species planariarum occurs in various marine and fresh-water Tur- 

 bellaria (Cepede, 1910), principally in Planaria torva. Bishop (1926) 

 found it in 70 percent of that triclad at Cambridge. Finding certain 

 differences from the forms in vertebrates, she kept it in the genus Sie- 

 boldiellina; but Cheissin (1930), followed by Bush (1934), did not 

 recognize any generic differences. Speculation on the origin of this di- 

 versity of hosts would, with our present information, be vain. 



