122 MR. H. CHARLTON BASTIAN’S MONOGRAPH 
stri; setæ none; papille none(?). Pharyngeal. cavity modified into a simple 
hollow exsertile (?) spear. (Esophagus having a distinct rounded muscular swell. 
ing at termination ; lumen of esophagus thread-like. Zntestine not distinctly de- 
fined, from extremely small number and colourless nature of hepatic granules; 
internal or intestinal tube proper often very distinct. Vulva at. about the com. 
mencement of posterior third of body. Uterus unsymmetrical. Spicules simple, 
slender, curved. Accessory piece none. Æxcretory gland having rather rigid, 
curved duct, opening posterior to junction of esophagus with intestine. Lateral 
wessele ... s | 
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 Plectus, and 
two or three times in Zylenchus 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 4. parietinus, also within the intestinal canal, there have 
been a large number of small 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. 
What is their precise nature seems difficult to say at present. That their oceur- 
rence is exceptional, as well as other considerations, rather inclines me to the opinion 
that they are distinct organisms, perhaps belonging to the family Gregarinide, “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 helminthologists have observed in certain 
parasitic Nematoids. Speaking of Ascaris truncata, this distinguished naturalist says’: 
— Toutes les cavités interviscérales sont occupées, chez les mâles comme chez les 
femelles, par des vésicules independentes qui ont attiré Pattention de tous les helmin- 
thologistes, mais dont on n’a point indiqué la nature. Il semble qu’on ne peut dire 
autre chose, sinon que ce sont des productions parasites analogues aux acéphalo- 
cystes des mammifères.’ And a little further on (p. 220), after describing 4. macu- 
losa from the Common Pigeon, speaking of Rudolphi's observations, he adds: ale 
signale aussi dans le tégument des corpuscles orbiculaires diaphanes, beaucoup plus 
grands que les œufs, et qui rendent le corps presque tacheté, d’où le nom spécifique de 
maculosa. En disséquant ces ascarides, on voit en effet flotter avec les œufs, dans le 
Bauide, des vésicules larges de 0""-14 à Omm-30, sur la nature desquelles il est difficile 
d'étre fixé. Ce sont les mémes que l'on trouve aussi dans l'ascaride du alii et E. 
je crois analogues à des acéphalocystes.” 
1. A. AVENA, n. n (Plate X. Nes 97, 98.) 
Female, length 3,”, iu 
External Characters. Sese a white, eo very slightly at either — both of 
¥ 
i On our Promi Knowledge of the Gregarinide,” &e., ar E. Bar Skater, Journ. of eos, Soc., new y series, 
— vhs * Hist. Nat. des Helminthes, p. 219 
