THE SPOROZOA 



293 



Genus 2. Leptotheca, Thel, 



CLASSIFICATION. 

 ORDER Myxosporidia, Biitschli. 



SUB-ORDER I. PHAENOCYSTES, Gurley ( = Myxosporidia sens, strict.). 

 Spores relatively large, bilaterally symmetrical, with two or four polar 

 capsules, which are plainly visible in the fresh state. (Two anomalous 

 species of Myxobolus have but a single polar capsule in the spore.) Two 

 spores are formed in each pansporoblast. The trophozoite is an inter- 

 cellular parasite in all but the earliest stages. 



(a) Disporea, Doflein. Only two spores (i.e. one pansporoblast) are 

 produced in each trophozoite. The greatest length of the spore is at right 

 angles to the plane of symmetry, i.e. the sutural plane. Typically " free " 

 parasites (see p. 277). 



FAMILY 1. CERATOMYXIDAE, Doflein. With characters as above. 



Genus 1. Ceratomyxa, The"!., 1892. The valves of the spore-membrane 

 have the form of hollow cones, the extremities of which are prolonged into 

 more or less attenuated processes (Fig. 93). About nine species are 

 known, all from the gall-bladders of fishes. Type-species C. sphaerulosa, 

 Thel. (Fig. 93), from Mustelus and Galeus. 

 1895. The valves of the spore 

 membrane are not produced 

 into long processes as in the 

 preceding, and the sporoplasm 

 fills the whole space within the 

 spore-membrane not taken up 

 by the polar capsules (Figs. 

 104, 105). Six species are 

 known, four inhabiting the 

 gall-bladders of fishes, while 

 L. ranae, The"!., occurs in the 

 kidneys of Rana esculenta and suture ; p, spbropiasm; 

 R. temporaria ; L. 

 The"!., in the kidney-tubules 

 of the mackerel. Type-species L. agilis, The"l. (Fig. 104), from the gall- 

 bladder of Trygon vnlyaris. 



(b) Polysporea, Doflein. More than two spores, usually a vast number, 

 are produced in each trophozoite. The greatest length of the spore lies in 

 the sutural plane. 



While in general the Polysporea and Disporea are distinct enough in 

 all their characters, a transition between these two sections is furnished 

 by the genus Sphaerospora, which has nearly spherical spores, and of which 

 one species, S. elegans, Thel., is disporous. 



FAMILY 2. MYXIDIIDAE, Thel. The spores have two polar capsules, 

 and are without an iodinophilous vacuole (p. 289) in the protoplasm. 

 Typically " free " parasites. 



Genus 3. Sphaerospora, Thel., 1892. (Characters, see above.) Four 

 or five species are known, mostly from the kidneys of fishes, but 



Spore of 



agilis, Thel. (par. Trygon 

 enA), seen in the 



/ (From Wasielewski, after 

 remcola, Thclohan.) 



Fio. 105. 



Spores of Isptotheca 

 perlata, [= Chloromyxum 

 (Xphaerospora) perlata, 

 Gurley] (par. Acerina 

 cermta). (From Wasie- 

 lewski, after Balbiani.) 



