863 THE ANIMAL KINGDOM. 



Nemertea and Turbellaria, rarely in Arthropoda ; the Polycystidae, the 

 division to which the greater number of genera belong, are almost confined 

 to Insecta, but have been found also in Phalangidae and some Acarina 

 among Arachnida, and two are known from Urochorda. 



(ii) Amoebosporidia. This sub-class has been established by Schneider 

 for the genus Ophryocystis, represented by two species, O. Biltschlii, from 

 the Malpighian vessels of Blaps, and O. Francisci from Akis. The hosts 

 are beetles belonging to the family Tenebrionidae. The organism is amoe- 

 biform, with granular protoplasm, and more or less hyaline pseudopodia- 

 like processes, sometimes simple, sometimes branched, and probably 

 endued with extremely slow contractility. It is nucleated ; small indi- 

 viduals are uni-nucleate, larger multi-nucleate. The nucleus appears to 

 be vesicular with one or two nucleolar spots. The multi-nucleate masses 

 become spherical and divide into a number of uni-nucleate individuals, 

 connected to one another at a central spot by clear or somewhat granular 

 prolongations. They throw out pseudopodia-like processes from their 

 broader ends, and are detached by degrees from one another ; the con- 

 necting prolongations are slowly absorbed. Two uni-nucleate individuals 

 have been observed to conjugate and encyst. The cyst has a simple wall 

 in O. Francisci, but its contents give origin to a number of coats, one 

 within the other in O. Biltschlii. It is marked by an equatorial line, along 

 which it separates into two portions. The outer coats in O. Biltschlii 

 do so whilst their successors are forming. The two nuclei give origin 

 to six, and then the central region, with two of the nuclei which probably 

 conjugate, is converted into a spore ; the remaining nuclei and proto- 

 plasm degenerate into residual masses, which disappear. The ripe spore 

 is elliptical with pointed poles ; it has a double spore-membrane ; its 

 contents divide into eight (?) uni-nucleate falciform bodies and a ' nucleus 

 de reliquat.' It is rare for a cyst to contain two spores. 



(iii) Sarcosporidia. There are three Sporozoans included in this sub- 

 class two, Miescheria and Sarcocystis, which are found within the striated 

 muscle fibres of certain mammals, and one, Balbiania, recently discovered 

 in the sub-mucous coat of the large intestine of a Macropus penicillatus. The 

 two first are most commonly found in the diaphragm, walls of the abdomen, 

 eye-muscles, tongue, and the muscles of the thorax. The heart, pharynx 

 and larynx are also favourite localities. They occur in various Mammals, 

 especially the Pig, and have been detected in the Fowl and some other 

 birds. In size they usually range from 3 mm. downwards, but specimens 

 I in. long have been seen in the Rat, ain. in the Roe-deer. They are 

 usually elongate and pointed at the ends, but if the muscle fibres in 



