GENUS FOLUCULINA. 597 



into two more or less elongate and usually symmetrical, flattened, lappet-like 

 lobes or processes, the cleft between which is deepest on the oral or ventral 

 side ; peristomal fringe originating on the ventral side at the base of the 

 right-hand lobe, skirting the entire margin of the bilobate frontal border, 

 descending in a shortly revolute spiral manner into the oral aperture 

 on its arriving at its point of origin or base of the left-hand lobe ; 

 peristomal or adoral cilia very long, those of the general cuticular surface 

 exceedingly fine, disposed in even longitudinal rows ; anal aperture situated 

 close to the base of the left-hand peristomal lobe. Mostly inhabiting salt 

 water. 



A somewhat subtle question of priority has arisen in connection with the 

 adoption of the correct title for the various members of the present genus. The 

 earliest efficient diagnosis of the group was given by Claparede and Lachmann in 

 Miiller's 'Archives' for the year 1856, and in which they bestowed upon it the title 

 of Freia, a name borrowed from the pages of Scandinavian mythology. This 

 generic title is retained in their subsequent larger work ' Etudes sur les Infusoires,' 

 1858-1861, the Vorticella ampulla of O. F. Miiller being there recognized and fully 

 described as its type form. Meanwhile Dr. Strethill Wright published in the 

 Edinburgh ' New Philosophical Journal ' for 1858, the account of several animalcules 

 possessing similar structural characteristics and, unaware of Claparede and Lach- 

 mann's discoveries in a similar direction, conferred upon them the generic name 

 of Lagotia. Two years later * Dr. Wright acknowledged the priority of Claparede 

 and Lachmann's title, and described a supposed new form under the title of Freia 

 obstetrica. As shown, however, by Stein, in his monograph of the Heterotricha,! 

 the Vorticella ampulla of O. F, Miiller, which stands as the typical representative 

 of this genus, was recognized as the type of a new generic group by Lamarck so 

 long since as the year 18 16,:}: and for which he proposed the name of Folliculitia. 

 Stein furthermore points out that the name of Freia has been previously employed 

 by C. L. Koch in the year 1850 for the distinction of a genus of Arachnida, 

 but at the same time elects to retain Claparede and Lachmann's designation 

 on the ground of its widespread adoption. Paying strict regard to the laws of 

 scientific nomenclature there can be no question, however, that in a double sense the 

 generic name of Freia, as representing an infusorial group, must make way for 

 the Lamarckian one of Folliculina, which is herewith adopted. The structural 

 features of this genus correspond considerably with those of Stejitor, the chief devia- 

 tion from the latter type being the abnormal bilobate development of the peristome- 

 border and the permanent occupation by the animalcules of a rigid sheath or lorica. 

 Although so widely distributed, no examples of this generic group appear to have 

 fallen within the cognizance of Ehrenberg, who has in consequence passed over 

 Miiller's Vorticella ampulla as an imperfectly observed representative of the genus 

 Vaginicola, under which name it reappears in Pritchard's ' Infusoria.' A charac- 

 teristic feature exhibited by many of the representatives of the genus Folliculiiia 

 is afforded by the colour of the body-substance or parenchyma, which, in the 

 majority of instances, presents a remarkable dark bottle-green or blackish hue. 

 This coloration does not, as in most animalcules, result from the inception and 

 temporary retention of coloured food-particles, but is so intimately and inseparably 

 interblended with the substance of the parenchyma as to communicate its charac- 

 teristic tint to the externally secreted tests or loricae. 



Folliculina ampulla, Miill. sp. Pl. XXIX. Figs. 21-28. 

 Adult sheath or lorica glaucous or sea-green, when young transparent, 

 more or less ovate or flask-shaped, attached laterally with the neck bent 



* ' Quart. Journ. Mic. Science,' 1S62. t ' Infusionsthiere,' Ablh. ii., 1877. 



X ' liibl. des Anim. sans Vert.,' tuin. ii. p. 30. 



