GENUS A MBL YOPHIS. 385 



Euglena tuba, Carter. Pl. XX. Figs. 54 and 55. 



Body fusiform, subcylindrical, fish-shaped ; obtuse and bilabiate an- 

 teriorly, terminating posteriorly in a short, pointed, tail-like prolongation ; 

 eye-like pigment-spot and contractile vesicle anteriorly situated ; colour 

 green. Length 1-300". Hab. — Fresh water, Bombay : social. 



Although this animalcule in its normal free-swimming condition presents no 

 important distinction from Euglena viridis, it exhibits in its quiescent or encysted 

 state a highly characteristic deviation. In this condition, according to its dis- 

 coverer, the animalcules produce by exudation, as shown at PI. XX. Fig. 55, a common 

 reticulate, transparent, gelatinous basis, within the tubular ramifications of which they 

 secrete individually a flask-shaped cyst or lorica, having a round inflated basal 

 portion and a long tubular neck, the apical extremity of which is dilated like the 

 mouth of a trumpet. The relationship between the free-swimming animalcules 

 and these flask-shaped encystments cannot be said to be definitely determined. 

 Although not mentioned in the original description of this form,* Mr. Carter has 

 personally informed the author that the motile and encysted conditions were not 

 observed in direct connection with one another, but that the tank from which 

 they were taken, while found on one occasion to yield the free-swimming Eiiglence 

 in abundance, produced in the place of these, when visited a few days later, a com- 

 plete surface-stratum of the encysted structures immersed in their gelatinous network. 

 The contour of these cysts, with their elongate necks and everted apertures, is so 

 distinct from what is met with among the members of the ordinary Euglenidse, but 

 at the same time corresponds so remarkably with that of the flask-shaped loric^e of 

 the collared monad Salpiugoaca ampJwridium and its allies, that the author is half 

 inclined to suspect that a further investigation may elicit that this presumed encysted 

 state of Euglena tuba is in no way connected with the free-ssvimming animalcules 

 observed by Mr. Carter, but represents the quiescent condition of an as yet unde- 

 scribed type of the Choano-Flagellate order. Should these premises prove correct, 

 this organism will constitute a new generic type of the group indicated, corre- 

 sponding closely with the mucous inhabiting Phalanstcnum, but representing in 

 itself a most interesting departure in the direction of the sponges. 



Euglena — Supplementary . 



The Euglena ovum of Ehrenberg is now referred by Stein to the genus Chloro- 

 peltis, and the E. pyruni and longicauda of the same authority to that of Phacus. 

 The Euglena mucronata of Perty, with its pointed tail and finely striped cuticle, is 

 scarcely to be distinguished from E. spirogyra, while the E. obscura of Dujardin 

 would seem to represent a variety only of E. viridis. De Fromentel has introduced 

 into his work, f as new species of Euglena, several forms, all of which, however, 

 might be referred to E. viridis, and differ from each other only in minor points of 

 contour and coloration. The reproduction of these names with their diagnoses 

 would serve only to further burden and embarrass the synonymy of the genus. 



Genus II. AMBLYOPHIS, Ehrenberg. 



Animalcules uniflagellate, free-swimming, elongate, flexible and 

 changeable in form, rounded posteriorly, never exhibiting a tail-like pro- 

 longation of this region ; endoplasm coloured green ; an anterior eye-like 

 pigment-spot usually present ; the front margin apparently bilabiate, in- 

 dicating the presence of an oral aperture resembling that of Englena, this 

 sometimes followed by a distinct pharyngeal tract. 



* 'Ann. and Mag. Nat. Hist.,' April 1869. f 'Etudes sur les Microzoaires,' Paris, 1876. 



2 C 



