4 1 2 ORDER FLA CELL A TA -E US TO MA TA . 



subequal ; endoplasm containing two lateral pigment-bands, one or more 

 coloured eye- specks usually developed. Inhabiting fresh water. 



Known only by the figures and descriptions of Ehrenberg, the single type-form 

 of this genus has been regarded as an entirely doubtful species, and, together 

 with Syiiaypta and Urogkfia, been even discarded by Mr. Carter as spermatic or 

 developmental phases of the vegetable types Volvox or Spharophrya. As recently 

 shown by Stein, however, this form possesses a sound claim for independent recog- 

 nition. It is further demonstrated by this authority that Ehrenberg was wrong in 

 assigning to the spheroidal colonies the possession of a common gelatinous matrix, 

 as in Syiicrypta and Uroglena, in addition to the individual loricee. What Ehrenberg 

 took for such an element were probably the minute, thickly set, filamentous or spinous 

 processes, now made known by Stein to be developed throughout the external 

 surfaces of the loricas of the type in question, but which are to be recognized as 

 distinct structures only when the organism is examined with the aid of an exceedingly 

 high magnifying power. The presence of two flagella, eye-specks, colour-bands, and 

 other histologic details, are also for the first time demonstrated by this authority. 



Synura tivella, Ehr. Pl. XXIII. Figs, i and 2. 



Loricae pyriform, tapering posteriorly, sometimes prolonged in a stalk- 

 like manner, their external surface beset with evenly developed spinous 

 processes ; contained animalcules almost entirely filling the cavities of the 

 loricae, their posterior extremity produced towards and adherent to the 

 bottom of the same ; flagella subequal, eye-like pigment-specks minute, 

 two in number, sometimes absent ; a large vacuolar space, apparently 

 representing a pharyngeal dilatation, developed at the anterior extremity ; 

 colour-bands produced equally throughout the length of the two lateral 

 borders ; contractile vesicles two or three in number, posteriorly located ; 

 endoplast situated in the middle line, immediately behind the two eye-like 

 specks. Length of individual loricae 1-740" ; diameter of spheroidal colonies 

 1-350" to 1-200", these latter often consisting of as many as eighty zooids. 



Hab. — Pond water. 



' Stein regards the type figured by him as the eyeless variety of this species, 

 PI. XXIII. Fig. I, as identical with the Uvella virescens of Ehrenberg. Biitschli, 

 however,* figures and describes as representing this last-named organism an entirely 

 distinct form in which there is no lorica with its spinous processes and no conspicuous 

 pharyngeal dilatation, such species being here accepted as typifying the genus Uvella. 

 Stein has further proposed to unite with this organism the Alallomonas Plossliioi Max 

 Perty, which he regards as isolated individuals of Synura tivclla, with the setose or 

 spinous processes of their loricae greatly produced. Mallovwnas is, however, an 

 entirely distinct monoflagellate animalcule, having, as demonstrated by the author's 

 description and illustrations elsewhere submitted, nothing in common with the 

 Chloromonadidffi. 



Doubtful Species. 



Under the title of Rhodccssa grimselina, Perty figures and describes, apart from 

 Uvella virescens, a species apparently belonging to this same genus Syjiu>-a. No 

 reference to a distinct lorica is given, but the margin of each body is reported to be 

 distinctly and finely crenulate. Except for two evenly developed bright green lateral 

 pigment-bands the body-substance is entirely transparent. The crenulation exhibited 

 represents probably the periphery of a separate lorica. The type was obtained by 



* ' Zeitschrift fiir Wissenschaftliche Zoologie,' Bd. xxx., 1S78. 



