232 



THE SPOROZOA 



(vide infra, p. 236). The reproduction of D. lacazei has been studied by 

 Laveran. By many authors this genus is united with the following. 1 

 Genus 4. Isospcra, A. Schn., 1881. Spores polyzoic. 

 I. ram, A. Schn., from the black slug Limax cimreo-niger (kidneys?), 

 characterised by having numerous sporozoites in each 

 spore (Fig. 61). 



FAMILY 3. TETRASPOROCYSTIDAE, Leger (Tribe Tetra- 

 sporea, A. Schn.). The oocyst contains four spores 

 (chlamydospores). 



Genus 5. Coccidium, Leuckart, 1879. The dizoic 

 spores are spherical or ovaL 



A very large number of species, confined, with few 

 exc eptions (see p. 206), to Vertebrate hosts, and occur- 

 Limax sp.), show- ring commonly in all kinds of Vertebrates. The type 

 z"fc spore! From an( l best - known species is the common C. oviforme, 

 Leuck -' 2 from tlie rabbit (Figs. 47 and 62), which is said 

 to be found occasionally also in man (see reference on p. 

 209). In Sauropsida the prevailing type is Diplospora (see above), but 



FIG. 61. 



FIG. 62. 



Spore formation in Coccidium oviforme, Leuck., from the liver of the rabbit. After Balbiani, 

 from Wasielewski. a, encysted individual (zygote) in which the protoplasm is beginning to 

 shrink away from the oval oocyst at the two poles. 6, the zygote has contracted itself into a 

 spherical form, c, segmentation into four sporoblasts. d, elongation of the sporoblasts to 

 form spores, e, four complete spores in the oocyst. /, single spore more highly magnified, 

 showing the two sporozoites and a small quantity of residual protoplasm. 



Coccidium raillieti, Le"ger, has been described from the intestine of the 

 slow-worm Anguis fragilis ; and C. delagei, Labbe, from that of the water- 

 tortoise Cistudo europaea ; while G. tenellum, Bailliet, with several varieties, 



1 Laveran, Mesnil, Schaudinn, and Blan chard are apparently of opinion that 

 Schneider's description of Isospora rara as polyzoic was erroneous, and regard this 

 species as tetrazoic, thereby making the genera Isospora and Diplospora synonymous. 

 Hence, since Isospora is the older name, they make use of it for all the species here 

 termed Diplospora. But until Schneider's type of Isospora has been re-examined, it 

 is somewhat prematiire to assume that so experienced and distinguished an investi- 

 gator was in error in describing it as polyzoic. 



2 But according to Labbe [4] the name Psorospermium cuniculi, Rivolta, 1878, 

 is prior to Coccidium oviforme, Leuckart, 1879 ; the correct designation of the 

 species would therefore be Coccidium cuniculi (Rivolta). According to Stiles [58], 

 on the other hand, the species was named Monocystis stiedae by Lindemann in 1865. 

 Since, moreover, the type-species of Eimeria (E. falciformis) has proved to be a 

 Coccidium, this author claims that Eimeria 1875, as a generic name, has priority over 

 Coccidium 1879. The conclusion is that Coccidium as a generic name should dis- 

 appear, and the Coccidian parasite of the rabbit's liver should be called Eimeria 

 stiedae (Lindemann). Liihe (48) is of the same opinion as regards the application 

 and validity of the generic names Eimeria and Coccidium. 



