PARAPHYSES. 



[ 491 ] 



PARASITES. 



P. compressnm, 'E.'=Plagiotoma lumbrici, 

 D. 



P. milium, E.=Enchelys nodulosa or tri- 

 quetra, D. 



Dujardin places this genus with the family 

 Paramecina. 



BiBL. Ehrenberg, Infus. p. 349; Dujardin, 

 Infus. p. 481 ; Stein, Infus., jjassim. 



PARAPHYSES.— The name appUed to 

 more or less delicate-jointed, hair-like fila- 

 ments which occur in small numbers around 

 and between the antheridia and archegonia 

 of Mosses and Hepaticaceae (fig. 25. p. 48, 

 fig. 331, p. 320). The same term is applied 

 to simple tubular, more or less clavate cells, 

 occurring in large numbers among the spore- 

 sacs (asci and thecce) of the Ascomycetous 

 Fungi and the Lichens (fig. 40. p. 66, fig. 

 402. p. 388, PI. 29. figs. 6, 12). 



PARASITES.— Under this head are to be 

 included a number of animals and plants 

 infesting other animals and plants, nourished 

 at the expense of their structures or juices. 

 Of the animal parasites, the chief portion 

 belong to the class Crustacea, order Si- 

 PHOSTOMA, class Arachnida, family Aca- 

 RiNA ; the class Insecta, orders Anoplura 

 and Strepsiptera; and the class En- 



TOZOA. 



The Plants parasitic on animals chiefly 

 belong to the class of Fungi, and they are 

 tolerably numerous, but many of the forms 

 wdiich have been described and named are 

 certainly not distinct plants. They will be 

 most conveniently enumerated under the 

 heads of classes of animals infested. 



1. Man and Mammalia. 



On the Skin. — Achorion Schoenleinii and 

 PucciNiA favus (the former probably an 

 earlier stage of the latter), on the hair and 

 in the follicles, in Favus. — Trichophyton 

 tonsurans, on the hair in Plica polonica 

 and Favus ; this appears to be a Torula- 

 like growth, probably not a mature plant. 

 Tr. ? sporuloides, C. Rob., occurs in Plica, 

 and Tr.l ulcerina, C. Rob., in the pus 

 of ulcers. — Microsporon Audouinii occurs in 

 the hair-follicles in Porrigo decalvans; M. 

 mentagrophytes, on the beard, &c. ; M. 

 furfur, on the skin of the chest, &c., in 

 Pityriasis versicolor. — The occurrence of 

 Mucor Mucedo on the skin, and of an Asper- 

 gillus in the external conduit of the ear, 

 nuist be regarded as accidental. 



On the mucous surfaces or in cavities. — 

 Sarcina ventriculi in the stomach, &c., 

 Torula cerevisice (?), ditto. Various species 



of Leptomitus, which must be regarded as 

 im])erfect mycelial growths, found in almost 

 all the cavities of the body. Oidium albicans, 

 Ch. R., the fungus of " Aphtha," probably a 

 peculiar condition of Penicillium; Lep- 

 tothrix huccalis, a filamentous growth con- 

 stant in the tartar of the teeth, probably 

 some allied mycelium. 



2. Birds. 



Various species of Aspergillus have 

 been found in the lungs and air-sacs ; their 

 introduction would appear to be accidental. 

 In the eggs of the common fowl, Dacty- 

 LiUM oogenum occurs not unfrequently, 

 sometimes on the membrane of the yolk, 

 sometimes on the outer membrane, just 

 beneath the shell. — Sporotrichum brun- 

 neum, Schenk, in the white of eggs, convert- 

 ing it into a brownish gelatinous mass. 



3. Reptiles and Fishes. 



On the skin of Tritons, as of Fishes, 

 AcHLYA is frequently extremely developed; 

 other obscure forms are also enumerated by 

 Ch. Robin. The same author describes the 

 Psorospermia of J. Miiller, as Algae allied 

 to the Diatomaceai, but they appear to be 

 pseudo-naviculae of Gregarinje. 



4. Insects 



are subject to the invasion of various para- 

 sitic fungi, among the most remarkable of 

 which is the Muscardine of the Silk-worm, 

 BoTRYTis bassiana, which sometimes occa- 

 sions enormous loss to the silk-cultivators. 

 This fungus grows in or upon any part of 

 the silk-worm, Bombyx mori, in its larva, 

 chrysalis and imago forms. It is not fully 

 developed until after the death of the insect, 

 but if the spores penetrate the body of a 

 living specimen and this is placed in a damp 

 and confined atmosphere, the germination 

 takes place, and a development of the fungus 

 ensues which destroys the tissues and organs, 

 finally causing death. It has been developed 

 on many other Lepidoptera which have been 

 inoculated with it, and even the larvae of 

 certain Coleoptera take it. It is very 

 common to find flies in autumn infested 

 with a fungus, a kind of muscardine of flies ; 

 this belongs to the genus Sporendonema ; 

 its mycelial filaments ramify in the interior 

 of the body, and emerge at the articulations 

 of the segments of the abdomen to bear fruit, 

 killing the fly. x\ number of so- called genera 

 of Fungi and Alga3 have been described by 

 Robin and Leidy as occurring in the iutes- 



