INFUSORIA AS PARASITES. 
307 
stance renders it ineligible for admission into the ranks of the 
Peritricha proper, and indicates rather its Heterotrichous 
affinities. More correctly, perhaps, it may, like one or two other 
abnormal forms, be accepted as a connecting link between these 
respective orders. 
The family of the Ophryoscolecidse includes two genera, 
Ophryoscolex and Entodinium , which are notable for their 
occurrence as parasites within the first and second stomachs 
of various ruminants, such as sheep and oxen. Although first 
recognized as true Infusoria, and receiving their characteristic 
title, as here given, from Professor Stein, there can be but little 
doubt that they represent the forms originally discovered 
by MM. Gruby and Delafond, described by them in the 
‘ Comptes Rendus’ for the year 1840, and there compared with 
Potifera. All the several species are distinguished by the 
possession of an indurated carapace, frequently adorned with 
spinous processes ; and both genera bear an anterior evertile 
and retractile adoral ciliary wreath, which in Ophryoscolex is sup- 
plemented by a second girdle of cilia, developed round the centre 
of the body. Unfortunately, no illustration of any repre- 
sentative of these very interesting genera has yet been pub- 
lished. According to the French authorities first quoted, these 
animalcules are found infesting the viscera of sheep in pro- 
digious numbers. In five centigrammes of alimentary matter 
taken from the first and second stomachs (rumen and reticulum) 
of sheep, they found that no less than one-fifth of the 
total weight was composed of the bodies of these organisms. 
In the third and fourth stomachs (psalterium and abomasum), 
on the other hand, only dead and empty carapaces were met 
with, the softer r iiutrient endoplasm or parenchyma, having 
been dissolved out by the gastric juices. Upon the facts just 
recorded, MM. Gruby and Delafond argue, that the food supply 
of ruminants, though ostensibly of a purely vegetable nature, 
consists to a very considerable extent of lower animal organisms, 
which develope freely and with great rapidity in the first and 
second stomachs of their hosts, but are killed and assimilated 
on passing into the third and fourth stomachal compart- 
ments. The free Vorticellidan type recently described by 
Engelmann under the name of Astylozoon fallax , having two 
spinous processes at the posterior extremity, would seem to 
correspond so closely with Ophryoscolex and Entodinum in all 
essential structural details that its relegation to the same family 
group appears desirable. 
But a single form out of the entire Hypotrichous order of the 
Ciliata (having vibratile cilia on the ventral surface only) has to 
be referred to the parasitic series now under consideration. This 
single type, the Kerona polyporum of C. G. Ehrenberg (Plate 
