INTRODUCTION TO PARASITOLOGY 



15 



on the names of persons, geographic lo- 

 calities, etc. They must, however, have 

 latinized endings. Both names are writ- 

 ten in italics. 



The name of the person who first 

 named each species and the date when he 

 did it are also part of its scientific name, 

 altho these are often omitted in non-taxo- 

 nomic writing. If the namer assigned the 

 species to a different genus from the one 

 which is accepted as correct, then his 

 name and date are enclosed in parentheses 

 and are followed outside the parentheses 

 by the name of the person who assigned 

 the species to its present genus with the 

 date when he did it. If there has been no 

 change in the genus designated by the or- 

 iginal author, parentheses are not used. 

 Thus, the common large roundworm of the 

 dog, Toxocara canis, was first described 

 by Werner in 1782, but he assigned it to 

 the same genus as the earthworm, Lum- 

 bricus. In 1905, Stiles established a new 

 genus, Toxocara, for this species. The 

 original name, then, was Lumbricus canis 

 Werner, 1782, and the presently accepted 

 name is Toxocara canis (Werner, 1782) 

 Stiles, 1905. Similarly, in the early days 

 of parasitology almost all tapeworms were 

 assigned to a single genus, Taenia. As 

 knowledge increased, more and more gen- 

 era were split off from it. The common 

 sheep tapeworm was called Taenia expansa 

 by Rudolphi in 1805, but in 1891 Blanchard 

 established a new genus, Moniezia, for it, 

 so that its correct name is now Moniezia 

 expansa (Rudolphi, 1805) Blanchard, 1891. 



Genera are grouped together into 

 families, families are grouped into orders, 

 orders into classes, and classes into phyla. 

 Each of these categories, and also each of 

 the lower ones, is known as a taxon (pi. , 

 taxa). Subfamilies and superfamilies, sub- 

 orders and superorders, etc. are often 

 used, and in some cases so many relation- 

 ship levels are recognized that it is neces- 

 sary to introduce cohorts, tribes, etc. 



Each family is based on one of its 

 genera, known as the type genus, and the 

 name of the family is obtained by attach- 

 ing the ending, -idae, to the root of the 

 name of the genus. Thus, Strongylus be- 



longs to the family Strongylidae, and 

 Trichomonas to the family Trichomonad- 

 idae. The subfamily ending is -inae. 



While the botanists long ago adopted 

 a system of uniform endings for the names 

 of their higher taxa, the zoologists have 

 never been able to agree on one. As a 

 consequence, it is impossible to determine 

 the ranks of the higher taxa with certainty 

 from their names. In the present book, 

 however, the system of uniform endings 

 proposed by Levine (1959) is used, so this 

 problem does not arise. These are: 

 Superclass, -asica; Class, -asida; Sub- 

 class, -asina; Superorder, -orica; Order, 

 -orida; Suborder, -orina; Supercohort, 

 -icohica; Cohort, -icohida; Subcohort, 

 -icohina; Superfamily, -icae; Family, 

 -idae; Subfamily, -inae; Supertribe, 

 -ibica; Tribe, -ibida; Subtribe, -ibina. 



Many scientific names appear quite 

 formidable at first glance. They have def- 

 inite meanings, however, and it helps in 

 remembering them to know what these 

 meanings are. Since most scientific names 

 are based on Latin or Greek, a knowledge 

 of some of the descriptive words from 

 these languages is helpful. Much informa- 

 tion can be obtained from a dictionary of 

 derivations such as that of Jaeger (1955). 

 The thorny -headed worm of swine is 

 MacracantJiorhynchus hirudinaceus. This 

 name is derived from the Greek. The gen- 

 eric name means "large {macr-) thorny 

 {acantho-) proboscis {-rhynchus)." The 

 specific name is derived from the scien- 

 tific name of the leech (Hirudo) and means 

 "leechlike"; it was given because the worm 

 is firmly attached to the intestinal wall and 

 looks vaguely like a leech. The name of 

 the whipworm, Trichuris, commemorates 

 an error. This nematode looks a good 

 deal like a buggy-whip, with a sturdy body 

 and a long, whip-like anterior end about as 

 thick as a hair. T'' . ne, however, 

 means hair-tail an ' "tir-head. This 



mistake was so offe. some scien- 



tists that they propos . to substitute 

 Trichocephaliis for j.richuris. This is 

 not permissible according to the rule of 

 priority of the International Code of Zoo- 

 logical Nomenclature, so the error re- 

 mains. 



