226 



THE AMERICAN MONTHLY 



[December, 



kills the organisms that may be pres- 

 ent, but also the spores which, in some 

 cases, are not killed bv boiling. For 

 this reason we have been led to ex- 

 periment with baked potatoes, as it 

 is probable that no spores can with- 

 stand the temperature of an oven 

 when potatoes are baked. The result 

 has been eminently satisfactory so far 

 as cultures oi M. luteus are concerned. 

 The potato may be baked, placed un- 

 der a bell-jar which has been heated 

 in the oven until thoroughly steril- 

 ized, and there is not much danger of 

 contamination. 



Notices of New Fresh-Water In- 

 fusoria. — II. 



BY ALFRED C. STOKES, M. D. 



Opercularia flicatilis^ sp. nov. 



Body elongate-ovate or somewhat 

 conical-vase-shaped, smooth, soft and 

 flexible, the length two and one-half 

 to three times the width ; when ex- 

 tended constricted beneath the peris- 

 tome border, widest in front of the 

 middle, tapering and attenuate poste- 

 riorly; when contracted broadly ovate- 

 pyriform or subspherical, thrown into 

 transverse folds posteriorly and bear- 

 ing anteriorly a snout-like, crenulated 

 and longitudinally plicate projection ; 

 parenchyma of the body and ciliary 

 disc enclosing numerous green cor- 

 puscles, that of the peristome border 

 and posterior one-third of the body 

 usually colorless and finely granular, 

 the cuticular surface of the latter part 

 finely striate lengthwise ; peristome 

 border as wide as the body, some- 

 what everted, the margin crenulate ; 

 ciliary disc considerably and obliquely 

 elevated ; ciliary circles two ; mem- 

 branous collar large and conspicuous ; 

 pedicle rigid, finely striate longitudi- 

 nally, dichotomous, or umbellate with 

 three or more branches, and gradually 

 increasing in thickness from the point 

 of attachment to that of division ; 

 zooids attached in subsessile clusters 

 of from ten to twenty members ; nu- 

 cleusband shaped, curved, transverse- 

 ly placed anteriorly; contractile vesicle 



single. Length of extended body y^ 

 inch ; height of entire colony gL- to 

 ji^inch. Habitat. — Pond water ; at- 

 tached to Cer atop hy Hum. and Ana- 

 charis. 



These colonies are comparatively 

 so immense in size that they are ap- 

 parent to the unaided vision. They 

 occur in some profusion on the leaf- 

 lets of various aquatic plants, the 

 zooids there forming subspherical 

 clusters about ^-^ inch in diameter. 

 The foot-stalk, stout, erect and rigid, 

 presents two distinct methods of di- 

 vision : simple furcation into two ap- 

 proximate branches as in figure i, 

 and a trifid or quadrifid umbellate 

 formation with the branches bifur- 

 cated or not, as in the diagram (Fig. 

 2.) Which form shall be selected 

 seems to depend upon the vital ac- 

 tivity, and consequently the uncom- 

 fortably crowded condition, of the 

 zooids. 



In the contracted phase the poste- 

 rior transverse annulations closely re- 

 semble those characteristic of Epis- 

 tylis plicatilis Ehr. when in the 

 same state, and suggested the specific 

 name. They, in connection with the 

 anterior snout-like projection, with 

 the distinct marginal crenulatlons and 

 the conspicuous longitudinal plica- 

 tions, readily distinguish the species 

 from all other members of the genus. 



In Fig. I is shown a small colony 

 with the most usual form of foot- 

 stalk ; in Fig. 2 the comparatively 

 rare umbel-like division, while Fig. 

 3 exhibits a contracted zooid and 

 Fig. 4 the characteristic parts of an 

 extended individual. The quadx-ifid 

 division of the foot-stalk seems very 

 uncommon. 



A method of multiplication for the 

 dissemination of the species is by the 

 subdivision of the body into several 

 subglobose or pyriform parts, each 

 bearing a subcentrally located ciliary 

 girdle. At times one of these mi- 

 grant zooids attaches itself to the 

 primary foot-stalk of the colony and 

 secretes a long narrow individual 

 pedicle, thus complicating the animal- 



