Chapter XI 

 PHYLUM FUNGILLI 



Phylum 7. FUNGILLI Haeckel 



Order Gregarinae Haeckel Gen. Morph. 2: xxv (1866). 



Class Sporozoa Leuckart Parasiten der Menschen 1, part 1: 241 (1879). 



Phylum FuNGiLLi Haeckel Syst. Phylog. 1: 90 (1894). 



Class Sporozoaria Delage and Herouard Traite Zool. 1 : 254 (1896). 



Subphylum Sporozoa Calkins Biol. Prot. 249 (1926). 



Essentially unicellular organisms (the cells sometimes becoming multinucleate or 

 multiple, but remaining undifferentiated except in connection with reproduction); 

 commonly with a writhing motion; reproduction usually involving complicated sexual 

 processes and the production of walled cysts (spores); flagella absent except some- 

 times on the sperms; parasitic in animals. 



The class Sporozoa as originally published by Leuckart included the following 

 groups: (a) the gregarines, first described by Dufour (1826) as worms parasitic in 

 beetles: the generic name Gregarina Dufour (1828) refers to their occurrence in 

 crowds; (b, c) coccidians and psorosperms, different sorts of parasites discovered in 

 fishes by J. Miiller and Retzius (1842); and, doubtfully, (d) Miescher's tubes 

 {Mieschersche Schlduche), being certain abnormal growths in muscles. The cause of 

 the pebrine disease of silkworms, which Nageli (in Caspary, 1857) had named A^o- 

 sema Bomhycis, belongs to this group but was not originally included, presumably 

 because Nageli had considered it to be a schizomycete. 



It has subsequently become known that almost every species of the animal kingdom 

 is parasitized by one or more species of Fungilli. Not all of these parasites, but many, 

 are serious pathogens. Thus the Fungilli are a very important group and very num- 

 erous. The number of species duly registered by name and description is apparently 

 some two or three thousand; this is surely a small fraction of the number which exist. 



The transmission of disease by biting arthropods was first demonstrated when 

 Theobald Smith (1893) showed that the Texas fever of cattle, caused by Babesia 

 bige?7iina, is transmitted by ticks. 



All who have classified the Sporozoa or Fungilli have recognized two prime sub- 

 ordinate groups, the first including the gregarines and coccidians, the second includ- 

 ing the organisms which were formerly called psorosperms (Myxosporidia or Neo- 

 sporidia). In addition to the main bodies of these groups, there are certain organisms 

 which have resisted definite placement and have been assigned sometimes to one of 

 the main groups, sometimes to the other, and sometimes to additional main groups. 

 In the present work the two main groups are treated as classes and the groups of 

 uncertain relationship are included in the first. Clearly, this class is to bear the name 

 of Sporozoa Leuckart. Schaudinn's famous paper on parasites in the owl (1903) is 

 apparently authority for the widely entertained opinion that this class is artificial, 

 representing at least two lines of descent. In fact, the class appears natural with the 

 possible exception of some of the poorly known groups. The second class is marked 

 by positive specialized characters and is clearly natural; it is not clearly certain that 

 the second class is related to the first, and it is accordingly not certain that the phylum 

 is natural. The classes are distinguished as follows: 



