316 Miscellaneous. 
of the body. Pharynx very short and narrow; cesophagus strongly 
muscular, cylindrical, 1-47th in. long by 1-533rd in. broad ; ceso- 
phageal bulb pyriform, 1-178th in. long, 1-222nd in. broad. Ven- 
triculus dilated aleeform at commencement, cylindrical throughout. 
Rectum short, pyriform. enerative aperture forty-two annulations 
above the anal. Ovary double ; ova 1-333rd in. long by 1-400th in. 
broad. 
Length of body from 1-10th to 1-8th in. ; breadth at middle 1-95th 
in. Tail 1-14th in. long by 1-111th in. broad at middle. 
Hab. and Remarks.—Streptostoma agile and Thelastoma attenu- 
atum are found together principally in the commencement of the 
large intestine of Julus marginatus, in numbers of from one to fifteen, 
and less frequently in the small intestine with Ascaris infecta, in 
numbers of from one to six. It is remarkable, that although I have 
found from one to fifteen-of these two genera in nine-tenths of the 
animals examined, I have never yet been able to detect a single male. 
Thelastoma always has the mouth projected, whilst Streptostoma 
has it retracted, producing, in some measure, but by no means wholly, 
the difference in size of the oral aperture. 
At first I was inclined to think these two animals were different 
stages of the same species, but the adults uniformly correspond to 
the descriptions given, and in all cases contained more or less per- 
fected ova. 
Their movements are active, wriggling the body in a sigmoid manner 
and vibrating the delicate spiculated tail, which in sunlight resembles 
a shining acicular crystal. 
Thelastoma, from its form of cesophagus and narrower annulations 
and shorter tail than Streptostoma, occupies a position between the 
latter and Oxyuris. 
Gregarina, Dufour. Body consisting of two distinct cells. In- 
ferior cell the larger, marked with delicate, parallel, longitudinal 
lines, (muscular?) and filled with a fine granular matter, obscuring 
one or two nucleolo-nucleated-organic cells. Superior cell placed in 
a depression of the inferior, surmounted bya slight papilla in which 
may be detected two lines, apparently outlines, of an oral canal to 
the interior of the cell which is filled with granular matter; cell-wall 
amorphous and transparent. 
Gregarina larvata. Body opake white, cylindrical or fusiform, 
frequently considerably dilated at the middle of the upper third. 
Superior cell a flattened or depressed sphere, received about one-half 
into a depression of the inferior cell, surmounted by a papillary eleva- 
tion with traces of a communication with the exterior ; interior filled 
with a finely granular mass resembling oil-globules, and measuring 
from 1-15,000th to 1-7500th m. Length of cell, in smallest mdi- 
viduals, 1-123rd in. ; in largest 1-80th by 1-61st in. broad. Inferior 
cell elongated, cylindrical or fusiform, not communicating with the 
exterior nor with the interior of the superior cell; filled with a mass 
of granules resembling that of the superior cell, rendering the larger 
individuals opake, but translucent in the smaller ones, and usually 
obscuring one or two comparatively large nucleolo-nucleated-organic 
cells, measuring from 1-888th to 1-308th in. in diameter. Cell-wall 
