SYSTEMATIC POSITION OF THE ROTIFERA. 141 



The genus Cyphonantes, instituted by Ehreiiberg upon two animalcules 

 found in water from the Baltic, is certainly not a Cilio-crustacean at all. 

 From the figure alone, and still more from the description, it is obvious 

 that this creature has no alliance whatever with a Rotifer, except in the 

 ciliary movement. It is probablj'^ the larva of some marine animal, and 

 I should suppose that of an acephalous mollusc. 



II. With elongated, jointed foot, retractile, like a telescope. 



1. Callidina elegans, Ehr. ; var. rosea, Ferty ; cornuta, Perty. 



2. Hydkias cornigera, Ehr. 



3. Typhlina viridis, Ehr. 



4. Rotifer vulgaris, cltri7ius, erythrceus, macrurus, tardus, Ehr. 



5. AcTiNURUS nejjtunms, Ehr. 



6. MoNOLABis conica, Ehr. 



7. Philodina erythrophthahna, roseola, macrostyla, citrina, acu- 



leata, megalotrocha, Ehr. 



III. With elongated, jointed, non-retractile foot. 



1. ScARiDiUM longicaudum, Ehr. 



2. DiNOciiABis Pocillum, tetractis, paiipera, Ehr. 



IV. With a short foot and long pedal forceps. 



1. NoTOMMATA (?) tigrts, longiseta, Ehr. 



2. MoNOCERCA rattus, hicornis, valga, Ehr. 



3. FuRCULARiA gibba, Forficula, gracilis, Ehr. 



4. MiCRODON clavus, Ehr. 



The genus Microdon, which I have never seen, would appear, from the 

 observations respecting it communicated by Ehrenberg and Perty, to be 

 worth attention. I imagine it may represent a male Cilio-crustacean. 



V. With short foot and pedal forceps, which are of equal length with, or 



somewhat shorter or longer than the foot. 



1. Hydatusta senta, hrachydactyla, Ehr. 



2. Pleurotbocha gibba, constricta, leptura, Ehr. 



3. Furcularia Bheinhartii, Ehr. (probably not a Furcularia, 



but a Notommata), 



4. Notommata tuba, petromyzmi, saccigera, copeus, centrura, 



brachyota, collaris, naj'as, aurita, gibba, ausata, decipiens, 

 felis, parasita, tripus, Ehr. ; tardigrada, n. sp. ; vermicu- 

 laris, Duj. ; roseola, onisciformis, Perty. 



5. LiNDiA torulosa, Duj. 



6. Synch^ta pectinata, baltica, oblonga, tremula, Ehr. 



7. DiGLENA grandis, forcipata, aurita, catellina, conara, caj)!- 



tata, caudata, Ehr. 



8. Rattalus lunaris, Ehr. 



9. DiSTEMMA forficula, setigerum, marinum, farcipatum, Ehr. 



10. Triophthalmus dorsualis, Ehr. 



11. Eospora najas, digitata, elongata, Ehr. 



12. Cyclogena lupus, elegans, Ehr. 



13. Theorus vernalis, imcinatus, Ehr. 



Ehrenberg's genus, Enteroplea hydatina, is the male of Hydatina senta ; 

 and his Notommata gramdaris stands in the same relation to Notommata 

 brachionus, which latter genus, however, is placed far more correctly 

 under the genus Brachionus thnn under Notommata. Diglena granularis, 

 Weisse, lastly, is the male of T). catellina, Ehr. 



