246 Prof. H. Fol on the Family Tintlnnodea. 



recognize the continuous inner lamina which closes the aper- 

 tures of the trellis. 



The three other species of Dictyocysta described by Hackel 

 have the test pierced with much larger apertures ; and it 

 seems to me difficult to believe that a continuous wall could 

 have escaped observation had it existed. Provisionally there- 

 fore we sliall consider these species as answering to the 

 character given by Ehrenberg for the whole genus, whilst 

 Dictyocysta cassis must be placed elsewhere. On comparing 

 the figure of Dictyocysta mitra^ Hackel, with the drawing 

 given by J. Mliller of the species named D. elegans by 

 Ehrenberg, it seems to me that these two tests are identical ; 

 D. mitra, Hackel, will therefore be only a synonym. 



The other forms observed by Hackel are referred to a new 

 genus [Codonella]^ characterized by the presence on the 

 peristome of a membrane in the form of a dentate collar, 

 bearing about twenty appendages like little shreds, each of 

 which is united to one of the teeth of the collar by a filiform 

 part. Beyond this membrane there is a circular row of long 

 motor cilia, twenty in number. Three species were observed, 

 one of which had the body covered with little cilia, while the 

 other two species have the body smooth. The test presents 

 protuberances and regular stride, and is covered in part with 

 agglutinated siliceous particles. Hackel supposes that the 

 forms described by Claparfede and Lachmanii, of which the 

 tests resemble those of his Codonelhv, belong in reality to that 

 genus. This appears to me very doubtful ; for I have myself 

 observed a species of Tintinnodean (PI. XVII. fig. 5) of which 

 the test much resembles that of CodoneUa campanella^ Hack., 

 and which, by the arrangement of the cilia of the peristome, 

 proves to be a true Tintinnodean, and not a CodoneUa. 



Hackel at once raises the two genera Dictyocysta and Codo- 

 neUa into two families distinct irom the Tintinnodea : this is 

 a rapid mode of doing business ; and I believe that his family 

 Dictyocystida in particular has no right to exist. As to that 

 of the Codonellida, it may subsist, at any rate until the struc- 

 ture of the CodoneUcB is better known. 



I propose the following classification, which has no preten- 

 tion to be any thing more than a provisional arrangement. 



Family Tintinnodea, Clap. & Lachm. 



Test in the form of a little bell, free. Animal conical, 

 retractile, attached to the test by a retractile peduncle without 

 strise or distinct layers. Periphery of the body garnished 

 with very fine vibratile cilia, or completely smooth. 8upe- 



