834 ORDER TENTACULIFERA-SUCTORIA. 



pended within the lorica, occupying about one-half of its cavity, bearing two 

 antero-lateral fascicles of suckers ; contractile vesicle single ; endoplast 

 ovate. Length of lorica 1-150". HAB. Salt water. 



This species was originally figured by Stein as the probable Acinete phase of 

 Cothurnia maritima. 



Acineta mystacina, Ehr. 

 PL. XLVI. FIGS. 40-43 AND 57, AND PL. XLVIII. FIG. 41. 



Lorica urceolate, subdivided at the anterior or distal margin into 

 five or six acuminate, triangular, valve-like lobes, which are bent inwards 

 and cover the aperture in a lid-like manner; body subspherical, freely 

 suspended within the lorica, bearing five or six fascicles of capitate 

 tentacula, which are extended through the fissure-like clefts between the 

 valves of the lorica ; contractile vesicle single ; endoplast rounded or 

 ovate ; pedicle varying in length from a less magnitude to four or five times 

 the length of the lorica, formed ;out of a hollow, attenuate, posterior 

 extension of the walls of the lorica. Length of lorica 1-120". 



HAB. Fresh water, on Lemncs and other aquatic plants. 



This form was originally described and figured by Stein as the Acinete phase of 

 Vaginicola crystallina. Claparede and Lachmann observed this species multiply by 

 the process of transverse fission, and ascertained that the separated product was, at 

 the time of its release, densely clothed with fine cilia, in addition to bearing the cha- 

 racteristic suctorial tentacles. In accordance with the observations of Stein, the 

 propagation of this species may be accomplished in a yet more abundant manner, 

 through the development of hypotrichously ciliate embryos, which are passed out of 

 the body and deposited singly within pocket-like diverticula of the parental mem- 

 brane ; these being extruded between the valves of the lorica, remain for some little 

 time attached apparently to the outer wall of this structure, as shown at PI. XLVI. 

 Figs. 40 and 43. In some instances no less than four or five of these embryonic 

 bodies are represented by Stein as attached to the distal border of a single zooid. 

 As recognized by the authority last quoted, the length of the hollow pedicle in this 

 type with relation to that of the lorica it supports varies very considerably, being 

 in some instances quite rudimentary or represented by a short conical elongation 

 only of the substance of the lorica, or in opposite cases equalling or surpassing the 

 altitude of the lorica. Mereschkowsky * has figured and described a variety of this 

 type in which the pedicle is very much more attenuate, being equal in length to from 

 five to seven times that of the lorica. Examples of this variety, for which 

 Mereschkowsky has proposed the title of Acineta mystacina var. longipes, have been 

 quite recently, October and November 1881, received by the author from two 

 different localities, namely, through Mr. J. Thomas from the neighbourhood of 

 Epping, and through Mr. Thomas Bolton from the Birmingham district. In the 

 last-named instance the animalcules were very abundantly developed, in company 

 with Acineta grandis, A. lemnarum, and Dendrosoma radians, on the leaves of 

 Nitella, Many of these were observed undergoing the process of transverse fission 

 in the manner described by Claparede and Lachmann. Some interesting drawings 

 and very abundant colonies of the more typical short-stalked variety of this species 

 were remitted to the author by Mr. F. W. Phillips in August 1881. Among the new 

 data elicited by Mr. Phillips may be mentioned the fact that the tentacles, when 

 contracted, exhibit, under high magnification, a distinct zigzag or spiral aspect, such 

 appearance being due to the presence of a delicate external spiral fibrilla analogous 



Protozoen des Nordlichen Russland," ' Archiv fiir Mikr. Anatomic,' Bd. xvi., 1878. 



