THE AMOEBAE 



133 



Vahlkanipfia lobospinosa (Craig, 1912) 

 Craig, 1913 is another coprophilic species. 

 Becker and Talbott (1927) found it in the 

 rumen of a cow in Iowa. Its trophozoites 

 are 10 to 24 ju long. Its cysts have 1 or 2 

 nuclei and are 7 to 11 (i in diameter. 



Noble (1958) found that Vahlkampfia 

 sp. appeared in fecal samples from Wy- 

 oming elk, bison, cattle, horses, sheep, 

 moose and marmots after storage at 4^ C 

 for a few days to a few weeks. The proto- 

 zoa persisted for several months. They 

 failed to survive in soil, nor were they 

 present in soil samples taken from areas 

 where elk, sheep or horses were present. 

 The trophozoites were 20 to 40 p. in diam- 

 eter, with finely granular cytoplasm 

 filled with food vacuoles and other parti- 

 cles. A contractile vacuole was present. 

 The pseudopods were broad, usually slug- 

 gish but sometimes formed almost explo- 

 sively; often there was only a single, 

 large pseudopod. The nucleus was ves- 

 icular, with a large, central endosome 

 occasionally appearing to be composed of 

 several closely packed granules. Peri- 

 pheral chromatin was rarely present, 

 altho a ring of minute granules was often 

 present just within the nuclear membrane. 

 The cysts were 8 to 15 in in diameter and 

 almost exclusively mononucleate. The 

 nucleus was different from that of the 

 trophozoite. Its central endosome was 

 usually smaller than in the trophozoite 

 and often composed of several granules, 

 and the peripheral chromatin was distinct, 

 arranged in irregular clumps and often 

 forming a crescent. A large vacuole and 

 irregular chromatoid bodies, many of 

 which resembled those of Entamoeba his- 

 tolytica, were present. Noble believed 

 that many of the cysts found in animal 

 and human feces and described as those 

 of Entamoeba are actually of the Vahl- 

 kampfia type. 



Noble (1958) cultured this species at 

 both 4° C and room temperature on the 

 surface of agar- plates containing 1 . 5% 

 agar, 0. 05% yeast extract and 0. 05% pep- 

 tone. The cultures held at room temper- 

 ature became moldy after 6 weeks and 

 were discarded, but Vahlkampfia was 

 present for 3 months without attention in 

 those held at 4° C. 



FAMILY ENDAMOEBIDAE 



Members of this family are parasitic 

 in the digestive tract of vertebrates and 

 invertebrates. The genera are differen- 

 tiated on the basis of nuclear morphology. 

 Four genera contain parasites of domestic 

 animals and man, but only two of these 

 contain pathogenic species. However, it 

 is important to be able to identify the var- 

 ious species in order to know whether an 

 infection with a pathogenic one is present 

 or not. 



Genus ENTAMOEBA Casagrandi and 

 Barbagallo, 1895 



The nucleus is vesicular, with a com- 

 paratively small endosome located at or 

 near its center, with or without periendo- 

 somal granules around the endosome, and 

 with a varying number of granules around 

 the periphery of the nucleus. Cysts are 

 formed; they contain 1 to 8 nuclei and may 

 or may not contain chromatoid bodies 

 (rod-like bodies which stain with hema- 

 toxylin and which are absorbed and dis- 

 appear as the cysts mature). This genus 

 occurs in both vertebrates and inverte- 

 brates. 



The name of this genus was the sub- 

 ject of one of the most famous taxonomic 

 controversies in protozoology (Dobell, 

 1938; Kirby, 1945). The genus Endamoeba 

 was established by Leidy in 1879 for an 

 amoeba of the cockroach, Endamoebae 

 blattae. In 1895 and in ignorance of this 

 name, Casagrandi and Barbagallo intro- 

 duced the name Entamoeba for the human 

 amoeba, E. coll. The nuclei of these two 

 forms are very different, that of the cock- 

 roach species lacking a central endosome. 

 Since the appearance of the nucleus is the 

 most important differentiating character 

 between genera in this family, it is ob- 

 vious to a protozoologist that these forms 

 belong in different genera. However, the 

 first syllable of their names is derived 

 from the same Greek root. Hence the In- 

 ternational Commission of Zoological 

 Nomenclature was asked to decide whether 

 the name that had been given second 

 should be changed to something else (i.e. , 

 whether the two names were homonyms). 



