RESEARCHES IN HELMINTHOLOGY AND PARASITOI.OCtY. 141 



prominences of the lateral borders when the body is twisted. The 

 interior of the body is finely granular, often with one or more large 

 globules, probably consisting of a nucleus, and at times of contractile 

 vesicles or vacuoles. No mouth could be detected, although one 

 probably exists, as the animal often contains particles of solid food, 

 sometimes comparatively of enormous size. 



The great accumulation of parasites, apparently constantly exist- 

 ing in the White Ant. one of our most common insects, will afford 

 a new and wonderful source of delight to our microscopists. They 

 should be examined in a denser liquid than water, as this produces 

 tlieir rapid destruction. The white of an egg thinned with water 

 Prof. L. finds to be a good medium in which to examine these and 

 other minute parasites from the interior of animals. 



The nematoid worm hacis migrans, discovered by M. Lespes, so 

 abundantly existing within the Termes luciftigus, and also externally 

 in the nest of this insect, in France, Prof. L. has occasionally found 

 in the Termes flavipes. 



[May, 1877. No. 439. See Bibliography.] 



Remarks on Gregarines. — Prof. Leidy remarked that his recent 

 study of the Rhizopods had led him once more to make an examina- 

 tion of some of the Gregarines, regarded as pertaining to a nearly 

 related class. 



The Gregarines are especially parasites of the Articulata, most of 

 the known forms having been found in insects, crustaceans, mj'ria- 

 pods, and annelides. Most of those observed by himself were found 

 in vegetable and dirt feeders. The}' frequently occupy the aliment- 

 ary canal, but in some animals occupy other organs or the peri- 

 visceral cavity. With few exceptions, the Gregarines at maturity 

 consist of a comparatively large nucleated cell, which for convenience 

 may be named the body cell, continuous at one pole with a small 

 non-nucleated cell, which in like manner maybe viewed as the head 

 cell. Both cells are filled with fine globular granules, which in mass 

 give the Gregarines a milk-white appearance. No mouth or trace 

 of intestinal organs exists. The outer wall of the cells is a thick, 

 structureless, contractile endosare, and within this, in the body 

 cell, there is often perceptible, as in Gregarina larvata of our com- 

 mon Julus, a well-marked longitudinally striated and apparently 

 muscular layer. 



The motions of the Gregarines consist of a kind of peristaltic 

 action of the wall of the body cell proceeding from one to the other 

 end. 



