NOTES AND MEMORANDA, 91 



lated and naked, and does not form parts of an archegonium. Pro- 

 fessor Caruel altogether discards the old classification of Thallophytes 

 into AlgBB, Fungi, and Lichens, but does not propose any other in its 

 place, and thinks it probable that as our knowledge of some of its 

 forms increases, it will be broken up into several primary groups. 

 He considers it would be an advantage if the term Cryptogamia were 

 altogether discarded.* 



The Morphology of the Oxytrichina. — Some important obser- 

 vations have been made by Professor V. Sterki on this subject,f which 

 may be shortly summed up as follows : — ■ 



1. Form and Size. — The Oxytrichina and indeed the whole group 

 of Hypotricha are usually described as having a convex dorsal and a 

 flat ventral side. This is not imiversally true : 0. gihha {Amphisia 

 (jibha, Sterki) has the ventral side concave with prominent edges, 

 while other forms are equally convex on both surfaces ; one is rounded 

 and spindle-shaped, and another has a flat dorsal side. Distinct 

 varieties of some species have been observed, as well as undoubted 

 monstrosities. 



2. Body-substance — Consistency. — Muscle-strite (Myophanstreifen) 

 occur in some cases. In Stylonichia mytilus suffering from want of 

 water, all the protoplasm was seen to form a network enclosing com- 

 municating vacuoles in which was contained a watery fluid or 

 " serum." Probably the contractile vesicle is a modified vacuole. 

 There is an unbroken chain of transition forms between species with 

 a carapace and those possessing the greatest amount of " Meta- 

 bolicitat " or power of changing their form. 



3. Peristome. — The structui'e in the oesophagus of Stylonichia, 

 described as the mouth-cleft by Stein, and as a second undulating 

 membrane by Engelmann, is really a row of long, delicate, undulating 

 cilia ; the author calls these the endoral row. He also describes a row 

 of paroral cilia, inserted along the line of attachment of the adoral 

 row, and directed inwards. 



4. Ciliation. — Those cilia which are disposed in rows are usually 

 fewer in number and of greater size than they are usually rej^resented. 

 Thus Sterki counts forty to fifty large cilia in the adoral row of Stylo- 

 nichia mytilus, as against the 200 fine ones of Stein. There is no absolute 

 distinction in nature between styles and bristle-like cilia ; moreover, 

 in one and the same species intermediate forms are met with between 

 the finest cilia and the strongest " styles." The marginal and anal 

 cilia are of a flattened form ; the large frontal and ventral cilia of 

 Stylonichia and Oxytricha are often polygonal in section ; in S. mytilus 

 some of the frontal cilia are semicircular in section. The flattenino' 

 of cilia is most marked in the adoral set, which are so modified as 

 to form fan-like plates, called by the author membranelles CMem- 

 branellen) ; he finds them in all Oxytrichce as well as in Euplotce and 

 AmphidisccB, in the peritrichous Halteria and in Stentor. When in 

 action, the opposite edges of the row of membranelles give the 

 appearance of a double row of cilia. In the matter of the location of 



* Mr. A. W. Bennett, in ' American Naturalist,' vol. xii. p. 747. 

 t ' Zcitseh. f. wiss. Zool.,' vol. xxx. 



