122 MR. H. CHARLTON BASTIAN'S MONOGRAPH 



striic; setge none; papillae none(?). Pharyngeal cavity modified into a simple 

 hollow exsertile (?) spear. (Esopluujus having" a distinct rounded muscular swell- 

 ing at termination ; lumen of oesophagus thread-like. Intestine not distinctly de- 

 fined, from extremely small number and colourless nature of hepatic granules ; 

 internal or intestinal tube proper often very distinct. Vulva at aljout the com- 

 mencement of posterior third of body. Uterus unsymmetrical. Spicules simple, 

 slender, curved. Accessory ^)?'e<?e none. Excretory gland having I'ather rigid, 

 curved duct, opening posterior to junction of oesophagus with iutestine. Lateral 



vessels 



Movements sluggish. 



In a member of this genus, Aphelenchus parietinus, I have very frequently met with 

 certain bodies such as I have also recognized once in a species of the genus Flectus, and 

 two or three times in Tylenclms Davainii. In these specimens a remarkable condition 

 has been met with, in which, beneath the integument of the whole animal, in the general 

 cavity of its body, and, in A. parietinus, also witliin the intestinal canal, there have 

 been a large number of smaU spherical cellular bodies, simply granular-looking in this 

 last species, but in the two others presenting the appearance of small hyaline cells, 

 each of which contains a large, highly refracting, spherical central body -or nucleus. 

 Wliat is their precise nature seems difficult to say at present. That their occur- 

 rence is exceptional, as well as other considerations, rather inclines me to the opinion 

 that they are distinct organisms, perhaps belonging to the family Gregarinidce, "a 

 group of animals of very simple structure, met with in the intestine and other parts 

 of many insects and Annelids " ^ Whatever be their nature, they seem to correspond 

 pretty closely to what Dujardin and other helmiuthologists have observed in certain 

 parasitic Nematoids. Speaking of Ascaris trtmcata, this distinguished naturalist says^ : 

 — " Toutes les cavites interviscerales sont occupt'es, chez les males comme chez les 

 femelles, par des vesicules independentes qui ont attire I'attcntion de tons les helmin- 

 thologistes, mais dont on n'a point indique la nature. II scmble qu'on ne pent dire 

 autre chose, sin on que ce sont des productions parasites analogvies aux accphalo- 

 cystes des mammiferes." And a little further on (p. 220), after describing A. macu- 

 losa from the Common Pigeon, speaking of E-udoljihi's observations, he adds : — " II 

 signale aussi dans le tegument des corpuscles orbiculaires diaphnnes, beaucoup plus 

 grands que les oeufs, et qui rendent le corps presque tachete, d'oii le nom specifique de 

 maculosa. En dissequant ces ascarides, on voit en effet flotter avec les oeufs, dans le 

 liquide, des vesicules larges de O'"'""!^ a 0°"""30, sur la nature desqueUes il est difficile 

 d'etre fixe. Ce sont les memes que Ton trouve aussi dans I'ascaride du Perroquet, et que 

 je crois analogues a des accphalocystes." 



1. A. AVENiE, n. sp. (Plate X. figs. 97, 98.) 

 Female, length -^", breadth i^". 

 External Characters. — Body white, tapering very slightly at either extremity, Ijoth of 



' " Oil our Present Knowledge of the Gregarinidce" &.C., by E. Ray Lankester, Journ. of Microsc. Soc, new series, 

 Tol. iii. p. 83. " Hist. Nat. des Ilelminthes, p. 21."). 



