418 SUililARY OF CURRENT RESEARCHES RELATING TO 



Opisthosti/Ia is a new genus, the constituents of the colonies of which 

 resemble those of Bhabdostyla, " but the rigid pedicel curved near its point 

 of attachment to the submerged object, this part acting when the zooid is 

 contracted like a spring, and throwing the animalcule and the otherwise 

 inflexible footstalk backward through the water, the whole immediately- 

 becoming upright by the recoil of the curved extremity of the pedicel." 

 0. annulata is a new species, and Rhahdosti/la pusilla, described by the 

 author in 1886, clearly belongs to this genus. Acinetactis mirabilis g. et 

 sp. n. differs from Adinomonas by having two flagella, and by the distinctly 

 capitate character of tho filamentous pseudopodia, which are often con- 

 spicuously pin-like in appearance. The flagellum may be temporarily 

 adherent, and its pressure in addition to the habitually vibratile appendage 

 necessitates the formation of a new family which may be called Acine- 

 tactidse. 



The other new species described are Masligamoeha longifihim, Anisonema 

 fusilla, Cryptogh na irimcata, Pyxidium urceolatum, Bhahdosfyla invaginata, 

 in which the ciliary disc has a characteristic conical form, Colpoda depressa, 

 in which the oral aperture is on the flattened ventral surface, Metopides 

 acuminata, Trichophrya sinuosa, which is much smaller than T. epistylidis, 

 Acinefa lacustris, which was found attached to Anacharis, and A. stagnatilis, 

 which was found on Myriophyllum. 



New Hypotrichous Infusoria.* — Dr. A. C. Stokes describes a new 

 genus of Hypotrichous Infusoria, for which he proposes the name of 

 Hemicycliostyla ; the forms are free-swimming, have twenty or more frontal 

 styles, arranged in two more or less semicircular rows, no anal styles, con- 

 tractile vesicles single or double, nucleus multij^le ; H. sphagni sp. n. is 

 1/50 to 1/60 in. long, one-fourth as broad, anal aperture dorsal, parenchyma 

 yacuolar, adoral cilia short. An allied form is distinguished by having 

 only one contractile vesicle, the absence of vacuolar spaces, and the develop- 

 ment of a conspicuous series of par-oral cilia on the inner edge of the left- 

 hand border of the peristome field ; it may be called H. trichoia sp. n. 



Urostyla gigas is a giant among Infusoria, having, when extended, the 

 length of 1/30 in. ; like the preceding species, it was found with Sphagnum. 

 There are from forty to sixty nuclei, which, if they have a connecting 

 thread, must have a very frail one, as the nuclear nodules float out freely 

 and separately from the disintegrated dead body. U. caudata sp. n. is an 

 ally. Three new species of Holosticha — H. caudata, H. liymenophora, and 

 H. similis—are described; as yet only one fresh-water species has been re- 

 corded. The new form will require an emendation of the generic definition, 

 as the peristomial membrane, the increased number of frontal styles (five 

 in H. hymenophora and about fourteen in H. similis^, and the double con- 

 tractile vesicle of the former, have not yet been noticed ; H. similis is alone 

 known to have a moniliform vesicle. In Urolepius dispar sp. n. the differ- 

 ence in the size of the ventral sette of the two median rows is unusually 

 well marked ; there is in it that prolongation of the anterior end as a 

 narrow crescent which is often seen in Infusoria, and which is usually styled 

 the upper lip ; Dr. Stokes believes that it is a continuation of the ventral 

 plane, and that it ought therefore to be called the lower \\]). U. longi- 

 caudalus sp. n., also found with Sphagnum, is unusually active, and is very 

 flexible and elastic. 



Eschaneustyla g. n. most nearly approaches Urostyla ; it has the ventral 

 seise in three unequal longitudinal lines; it is remarkable for having a 

 spherical pulsating vacuole, with canal-like diverticula, somewhat rcsem- 



* Pro(r. Amer. Phil. Sue, 1S8C, pp. 21-30 (1 pi.). 



