Hijdaiinaca ?\ infusorial animatxules. 631 



slender, toes thin and slightly curved. Found amongst Conferva. 

 Length 1-1 44th. 



Pleurotiiocha renalis (Ehr.) — Body elongate, slightly con- 

 Rtricted in front, toes short, frontal portion rather oblique, truncate, 

 pancreatic glands kidney-shaped (reniforrn). Length l-240th. 

 Berlin. 



P. tnmcata (Gosse.) — Body sub-cylindrical; truncnte behind 

 above the foot ; toes short, straight, slender. Length 1-1 /oth. 



Genus Furculakia. — The forked-fish Rotatoria have a single 

 frontal eye, and a forked foot. Rotatory organ compound. Longi- 

 tudinal muscles exist in F. gibba, and foot muscles in three species. 

 The oesophagus is very short, its head has two jaws, single toothed 

 {ynonogomphia) in two species, but not in the others ; a simple conical 

 alimentary canal {coelogastrica), with two ear-like glands, exists in 

 all the species, and a distinct ovarium, except in F. gibba, which 

 has only a contractile vesicle. Vessels, respiratory tubes, gills, &c., 

 are not recognizable. The eye in F. Reinhardti is placed upon a 

 brain-like mass. 



Dujardin has the following remarks on the Genus Furcularia : 

 " Hhe geuus Fitrcularia, one of the most numerous, undoubtedly 

 requires to be divided after new observations, but not according to 

 the number and disposition of the red points, as hae been done by 

 Ehrenberg. This author has indeed distributed some Systolides, 

 which appear to us to have the closest relations in form and mode of 

 living, into eight genera," viz., PI eurotrocha, Furcularia, Notommata, 

 Scaridiiim, Diglena, Distemma, Eosjjhoi'us, and Theorus, " but many 

 of these are purely nominal, and require a rigid revision." 



"The following are the principal species to be classed with 

 certainty among the Furcularia : 1 . F. furcata = Diglena caudata 

 (Ehr.), Diglena capitata, and Furcularia gracilis. 2. F. marina, 

 of the same size and form as the preceding, but marine, and dis- 

 tinguished further by the styles of its tail, which are twice as short, 

 and by its three-toothed but acute jaws, resembling a hook. 3. F. 

 forcipata, placed by Ehrenberg among the Diglena. 4. F. grandis 

 = Diglena grandis (Ehr.) 5. F. forficida, with which must also 

 he Si%s,oc\iL{eA Distemma forficida. 6. F. ea?u'cM/ff, which Ehrenberg 

 with doubt refers to Diglena? aurita. 7. F. najas, to which belong 



