GENUS EUGLENA. 383 



Euglena oxyuris, Schmarda. Pl. XX. Fig. 26. 



Body elongate, subcylindrical, or ligulate, eight or nine times as long as 

 broad when extended, often spirally contorted, terminating posteriorly in 

 a long, slightly curved, spur-like, caudal prolongation ; cuticular surface 

 obliquely striate ; amylaceous corpuscles cylindrical or elliptical, often very 

 numerous; colour green. Length 1-130". Hab. — Freshwater. 



The simple obHque striation of the cuticular surface, and less conspicuous deve- 

 lopment of the caudal spine, serve to distinguish this type from E. spirogyra. 

 The figure here given of the species, reproduced from Stein's drawings, represents 

 an animalcule in its more abnormal contorted condition. 



Euglena deses^ Ehr. Pl. XX. Figs. 52 and 53. 



Body elongate, vermicular, cylindrical, fifteen to twenty times as long 

 as broad, acutely pointed posteriorly when extended, but capable of assuming 

 the most protean contours ; cuticular surface smooth ; colour green ; amyla- 

 ceous corpuscles acicular. Length 1-760" to 1-240". 



Hab. — Pond water, among Lemnae. 



The figures here given are reproduced from Stein's recently published volume ; 

 that represented at Fig. 53 is described in the index as a young non-flagelliferous 

 example, whose locomotion is effected by peristaltic movements of the body. 

 According to Ehrenberg, this species never swims, but confines its motions to 

 sluggish creeping and twisting, 



Euglena acus, Ehr. Pl. XX. Figs. 24 and 25. 



Body very slender and elongate, from seven or eight to ten or twelve 

 times as long as broad, tapering towards both extremities, the anterior 

 end abruptly truncate, the posterior one acuminately pointed ; cuticular 

 surface smooth ; colour bright green ; a red eye-like pigment-spot usually 

 developed ; contractile vesicle conspicuous, anteriorly situated ; amylaceous 

 corpuscles numerous, elongate rectangular. Length 1-570" to i-iio". 



Hab. — Fresh and brackish water. 



Quite recently, November 1880, the author has received examples of this species 

 from the neighbourhood of Birmingham through Mr. Thomas Bohon. The speci- 

 mens thus examined yielded an average length of 1-150", and were remarkable for 

 the fact that, excepting for the anteriorly developed eye-like pigment-spot, their 

 body-substance was perfectly transparent — a circumstance attributable probably to 

 their having been for a long while deprived of their ordinary food-material. All 

 the examples were exceedingly attenuate, their greatest central breadth usually 

 scarcely exceeding that of the truncate anterior border. Their deportment in the 

 water, unlike that of most representatives of the genus Euglena, was remarkably 

 stiff. On rare occasions only were they observed to flex their bodies to the extent 

 represented at Pl. XX. Fig. 25, while in no instances did they exhibit protean 

 contractions and expansions as attested to in other of Stein's recent delineations. 

 Such metamorphic properties are apparently, in accordance with the index to his 

 figures, manifested chiefly by the older zooids. A number of examples were 

 observed with their more attenuate posterior extremities affixed to the glass slide or 

 accompanying organic debris, the movements of their flagella under such conditions 

 causing their stiff acicular bodies to revolve in circles as though on a pivot. Not 

 unfrequently a number of zooids becoming attached in this manner close to each 



