Trachelina.l infusorial animalcules. 579 



the extremities. The special organs for digestive juice not distinct. 

 Size 1-1 20th. 



"We here append those genera, named by Dujardin, having a near 

 affinity with Bursaria. These are, Phgiotoma, Kondylostoma, Opalina, 

 and Panophrys. Here too must be described the genera Acineria and 

 Pelecida (Duj.) as allies of Trachelius. 



"With reference to the two first named genera, Phgiotoma and 

 Kondylostoma, sufficient has been said in the remarks on Bursaria. 

 The third, Opaxina, is a genus constituted by M. M. Purkinje and 

 Valentin, and accepted by Siebold as well as by Dujardin. The 

 species called by Ehrenberg Bursaria ranarum, is the OpaUna ra7iarum 

 of those other authors ; or indeed this Ojjalma appears the representa- 

 tive of B. ranarum, B. intestmalis, B. nucleus, and it may be also of 

 other Bursaria of Ehrenberg, if, as some maintain, they arc only 

 varieties and not species. (Ann. N. H. v. 18, p. 441.) 



The Opalince are characterized by being oval or oblong, with an 

 oblique cleft indicating a mouth towards the anterior extremity 

 (Duj.) ; though, according to Siebold, they have no mouth. " They 

 are parasitic chiefly in Erogs and Annelida, and form but an artifi- 

 cial and pi'ovisional genus, for if mouthless, they belong to the 

 Parameciens ; if they possess a mouth, to Leuco2)hrys." 



Opalina Ltimhrici. — Body oval; depressed; narrower in front, 

 tnmcated behind. Length l-185th to l-145th. Eound in Lumbricus. 



0. na'idum. — Body oblong, or very elongated, nearly cylindrical, 

 marked with longitudinal and transverse strise and with scattered 

 vacuolae ; a fold, proceeding from the anterior extremity, extends to 

 nearly the middle. Length 1 -260th to l-130th. Eound in the 

 Nai's (one of the Annelida) f. 28-29, pi. xxi. 



Genus Panopheys. — Body ciliated throughout; oval, depressed, 

 contractile ; becoming ovoid, or even globular during contraction ; 

 surface marked by straight or oblique strise, crossing one another, and 

 beset with corresponding rows of cilia; mouth lateral. Dujardin 

 writes, — "Being deMrous of characterizing Bursaria by the row of 

 large cilia — en moustache, which lead to the mouth, I have thought 

 it right to establish a new genus for certain Bursaria of Ehrenberg, 

 which are devoid of this character, and whose mouth is surrounded 

 by only ordinary cilia." Unlike the Paramecia, they have no ante- 



