Remarks on Gregarines

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196

[1877.

PROCEEDINGS OF THE ACADEMYOF

MAY 15. The President, Dr. RUSCHENBERGER, in the chair. Twenty-seven membhers present. Remarks on Gregarn.nes.-Prof. LEIDYremarked that his recent study of the Rhizopods lhad ledl him once more to make an examination of some of the Gregarines, regarded as pertainiing to a nearly related class. Tlhe Gregarinies are especially parasites of the Articulata, imost of the known forms having been found in insects, crustaceans, myriapods, and anneli(les. Most of those observed by hiimself were found in vegetable and dirt feedlers. They frequently occupy the alimnentary canal, but in some aniimals occupy otlher organs or the periivisceral cavity. With few exceptions, the Gregarines at maturity con1sist of a comparatively large nucleated cell, which for convenience may be named the body cell, continuous at one pole witli a small non-niucleated cell, which in like manner may be viewed as the lhead cell. Both cells are filled witlh fine globular granuiles, whichl in mass give the Gregarines a milk-white appearan ce. No mouith or trace of intestinal organs exists. The outer wall of the cells is a thick, structureless, contractile endlosarc; and withini tlhis, in the body cell, there is often perceptible, as in Gregarina larvata of our common Julus, a well-marked lonigitu(in)ally striated and apparently muscular layer. The motions of the Gi-egar-ines consist of a kind of peristaltic action of the wall of the body cell proceeding from one to tlle otlher end. In the Gregarines, so common in several species of our earthworms, the hiea(d cell is absent, anid the-efore is verv properly viewed as of a clifferent genus fiom the more ordinary Gregarina unider the niame of Monocystis. The 3ilonocystis agili.s is sausagelike in form, and is usallaly fi-om 1 to ;3 of a millimetre in length . In movement its conitractions may commence at one enid anid proceed towards the opposite enid, or it may commence at both ends proceedingof towards the middle, or may commence in the latter position anid plroceed towards the ends. Fr-oin the researches of Lieberkiilhn anid others, it appears that the Gregrarinles

of earthiworms

assume a globular

form anid become

encysted, and the grlanutilarconitents ai-e in a gm-eater measure iesolved inito navicula-slhaped germs, wlich hiave beeni naned l)seudonaviculte

or navicellre

or psor-osperms.

Lieberkilii

was led to

considler the amoeboid periviscei-al coripuseles of the ear-thworm, as amelba-like embryos dlerived fi-om the navicelle, buit it is very doubtful whetlher there is any relationship whatever between thie

1877.]

NATURAL

SCIENCES

OF PHILADELPHIA.

197

two. Both Gregarines and navicella-cysts are met with in the intestine of our common earthworm, but the cysts are to be found most frequently and abundantly in the sperm vesicles. In the six vesicles of an earthworm Prof. Leidy had cournted1540 mature navicella-cysts, toaether with a number of groups of immnature cysts. The mature cysts, readily visible to the naked eye, as minute pearly-wlhiteglobules, by transmitted light lhavea peculiar pale blue hue. They measure about i of a millimetre in diameter. A cyst burst open spread its navicelise over a millimetre square, and was estimated to contain about 2500. These were quite uniform in size, and measured 0.0133 mm. long and 0.00665 broad. E. Van Beneden has clearly traced the development of the Gregarina of the Lobster from Amoeba-like embryos, so that it is not improbable that similar embryos may be derived from the navicelle. The Gregarines are usually viewed as constituting the lowest class of the Protozoa, and hence the lowest of animals. From their structure and mode of development, Prof. L. considered them as holding a higher rank than Rhizopods, and occupying a position intermediate to these and the Infusoria. Prof. L. further stated that in a large earthworm, Lumbricus terrestris, from the yard of his residence, the posterior pair of sperm vesicles alone contained upwards of a thousand navicellacysts, besides several thousand Gregarines, Monocystisagzlis,exhibiting the varieties of condition, such as have been represented by Schmidt, Lieberkulin, and others. Many of the Gregarines were invested with motionless cilia, while other actively contracting individuals possessed no trace of these appendages. Some of the Gregarines further exhiibited transition stages towards transformation into navicella-cysts. The latter difLered from those previouslv mentioned in having but a single thin membranous layer for their wall instead of many layers. Prof. L. added that our eartlhworms,which appear to be the same as the common European species, likewise appear to be infested with the same variety and kind of parasites. Among the latter he lhadrepeatedly observed the infusorian Anoplophrya lumbrici, and also several different niematoids. One of these, which hiehad found in the sperm vesicles, appeared to be undescribed. It was certainly different from the Dicelis filaria found in the same organs by Dujardin. It appears nearly related with Anguillula, and may be regarded as such with the name of A. melancholica. Its characters are as follows: Body cylindrical, tapering at the ends, distinctly annulated. Head truncated, with the vertex convex, and perforated centrally by the mouth, and defined from the sides by an elevated anntluis. Tail conical, and ending in a short, thick conical process. Mouth a minute round pore, unarmed; pharynx a slhort narrow tube; cesophagus long, cylindroid, widening posteriorly, and rather abruptly narrowed at

198

PROCEEDINGS

the tanterior extremity;

OF THE ACADEMY

OF

[1877.

gizzard wider than the oesophagcus, cylin-

drical and(Irouinded at the extremijities; initestiie straight, iltensely black or blackish brown. Lengtll from 3 to 4 millimetres; tlhick-

ness at middle 0.15 m. Length of cesophagus 0.5 m., of grizzard 0.125 in., tlickniess 0.075 m., tlhiekness of intestine 0.05 m., leng-th of tail from anal aperture 0.175 nm. Color black, withi the aniterior enld vhite. All females. Sometimes nipwards of a dozen fotunid in the sperm vesicles of a sinigle earthworm. MAY 22. The President,

Dr. RUSCHENBERGER, in the chair.

Forty-tlhree members present. The death of Matthew Baird was annouinced. Ont Chilomonas.-Pr of. LEIDY remarked that while strolliing along tlle sandy beach at Cape May, N. J., he observed that in a number of l)laces, where the water of hollows had sunken away in the sand, a thin yellowisl-green film colored the surface. A portion of this greeni matter scraped up was put in a bottle with sea water. The lheavier sand subsided, and the gr een matter remainecl in suispenision, giving the water an olive-green color, remindingf one of the coloredl turbid liquor decanted from a jar of stale preserve(d olivts. The color was suspected to be due to the presencee of diatomes, but oni microscopic examination it proved to be caused by Inultitudeles of a greenish Monad, probably pertaining to the genuts CThilomzonzas.The imiinute flagellate infusorian is discoid-oval in form, witli a slight emargination laterally a short distance posterior to the fore extremity. Trhe emargination apparenitly incdicates the position of the mouithi,and from it projected a single delicate flarelluin, scarcely distinguishable. At timnesthie little creature assumed a more circular shiape, or becatne reniiform. It moved activelv forward, rollingf over firom one sidle to the otlher and rapidly vibrated the flagellum. Under a high power the animual appeared transparent and color less or faintly bluish, with two or thiree laige balls of a yellowish-green hiie, and several transparenit, colorless, and well-defined globules. In size the msonad raniged from the lI th to .I,th of an inlch in lengthi. Ani average-sized individual measured 0.008 mm. lonig, 0.006 broad, and 0.004 thick. On Enstatite.-Dr. GEORGE A. K6NIG placed on record the occurrence of Enstatite as one of the associates of cortinddumiin Georgia. The material came to Dr. A. E. Foote from a dealer in that State, with other specimenis, slhowing the characteristic associationls of cortndum, spin)el, anid chlorite. At first sight the minieral appears like fibrolite, altering into damourite, so well kilown firom corundtum localities.