THE AMERICAN 



MONTHLY 



MICROSCOPICAL JOURNAL. 



YoL. YIL 



Washington, D. C, May, 1886. 



No. 5. 



Notices of New Fresh-Water Infu- 

 soria. — T. 



BY DR. ALFRED C. STOKES. 



Physomonas elongata^ sp. nov. 

 (Figs T and 3). 



Body elongate-ovate, somewhat 

 changeable in shape, twice as long 

 as broad, often widest posteriori}^, 

 and somewhat curved toward one 

 side anteriorly ; free-swimming or 

 temporarily attached by a short, in- 

 conspicuous, posteriorly developed 

 pedicle; frontal border obliquely 

 truncate, the lip usually prominent ; 

 primary flagellum sub-equal to the 

 body in length, the secondary one 

 about one-third that length ; contrac- 

 tile vesicle single, small, spherical, 

 situated in the anterior body-half 

 near the lateral border ; endoplasm 

 colorless, slightly granular. Length 

 of body, s^Vtt inch. Habitat. — 

 Swamp water with decaying vegeta- 

 tion, fi'om South Florida. 



This conspicuously ditlers from 

 the previously recorded forms in the 

 absence of the subspherical contour 

 commonly considered characteristic 

 (jf the genus. The very short, tem- 

 porarily developed pedicle is another 

 well-marked point of divergence be- 

 tween this and the other two spe- 

 cies. Frequently no distinct pedicle 

 can be discerned, the attachment ap- 

 pearing to be accomplished by a 

 slight extension and conspicuous 

 acumination of the posterior extrem- 

 ity. Reproduction takes place by 

 longitudinal fission, the smaller more 

 nearly spherical resultant zooids be- 

 ing abundant in the same infusion 

 with the larger ovate individuals. 

 The species was abundant in its hab- 



itat. The contractile vesicle is placed 

 on one side near that part of the 

 frontal border opposite to the lip-like 

 projection. Its movements are quick 

 and snapping. 



Tctrainitiis variabilis^ sp. nov. 

 (Figs. 3, 4, and 5). 



Body soft, changeable in shape, 

 obovate, with the anterior border 

 obliquely excavate, a short lip-like 

 prominence at its upper angle, or sub- 

 pyriform or subspherical, the frontal 

 border rounded, the posterior ex- 

 tremitv obtusely pointed or evenly 

 convex ; flagella four, subequal, ex- 

 ceeding or equalling the body in 

 length, inserted near the centre of 

 the anterior extremitv ; contractile 

 vesicles two, situated near the frontal 

 border, not close togetlier ; nucleus 

 obscured bv the granular endoplasm ; 

 food engulfed at any portion of the 

 surface; body without grooves. 

 Length, x^i^ ^^ tttto i^ich. Habi- 

 tat. — Standing Avater with decaying 

 vegetation. 



This form markedly diflers from 

 the three previously described spe- 

 cies in the entire absence of the lon- 

 gitudinal grooves and flattened cutic- 

 ular surfaces characteristic of those 

 animalcules. The species here de- 

 scribed was observed among decaying 

 xcgetation with water from the cypress 

 swamps of South Florida. It was 

 accompanied by very many forms 

 familiar in our more northern waters, 

 and is itself probably not restricted 

 to Florida. 



Urceoltis sabulosus^ sp. nov. 

 (Figs. 6 and 7). 



Body flask-shaped, soft, flexible, 

 and elastic, normally compressed 



