694 SYSTEMATIC HISTOEY OF THE INFrSOEIA. 



denied hj Cohn, whose testimony is to be relied upon. The animal contained 

 ^vithin this loriea presents the typical features of the Rotatorian class, just as 

 some minute Crustaceans (Entomostraca), though enclosed between bivalved 

 cases, retain the internal organization of their more conspicuous and shel- 

 less allies. The Euchlanidota are provided with the various Eotatorian 

 appendages — these exist as set£e, uncini, spurs, or tactile organs ; and all are 

 pro\ided with the characteristic tail or foot terminating in one or two digits, 

 this organ being largely employed in locomotion, either as a rudder or as an 

 anchor. The hardened tegument forming the loriea is variously prolonged 

 into spines and other appendages. Sometimes these are most developed 

 anteriorly, at others posteriorly, whilst in Stephanops a broad expansion of 

 the front of the loriea is developed into a curious crystalline hood. The sur- 

 faces of the loriea Kkewise are variously sculptured and ornamented. 



The eye-speck, to which Ehrenberg has attached such importance in his 

 subdivision of this family, possesses, as Dujardin has pointed out, less value 

 as a basis of classification than the Prussian observer supposed ; but if the 

 observations of Ley dig prove correct, the organ acquires additional interest 

 fi'om the discovery of a refracting body in the eyes of EucJilanis iinisetata and 

 Steplianops lamelJaris. Should these observations be confirmed, they will do 

 much to remove all doubt respecting the visual character of these organs, — 

 doubts which are naturally suggested by the improbability of \isual organs 

 being given to the embiyo encased in the egg, whilst the matm-ed, active, 

 bustling animalcule becomes deprived of them when its life seems to render 

 theii' presence most necessary. The exact nature of the internal organization 

 of most of the Euchlanidota is yet uncertain, and requires further study; 

 but each form, when minutely examined, is found to approximate more closely 

 to the Rotatorian type. Thus, whilst all are provided with a muscular system, 

 Cohn has demonstrated that in Eiwlilanis the fibres are of the striped or 

 voluntary type. The same observer has also shown that Enchlanis dilatata 

 is bisexual, the males resembling those of Hydatina and Asj)IancJina in being 

 unsupphed with an aUmentary canal. These are approximations towards a 

 general reduction of the whole class to a common type of organization of a 

 higher character than was formerly thought to exist amongst Rotifera, but 

 at the same time very difi'erent to what was originally attributed to them by 

 Ehrenberg. The genus Lepadella developes itself occasionally in such myiiads, 

 in stagnant water, as to give a whitish turbidity to it. 



Ehrenberg's arrangement of the genera is given at p. 478. Dujardin 

 includes most of the genera in his family Brachioniens. 



Genus LEPADELLA (XXXIV. 430-433). — Eyes absent; foot furcate. 

 Several trochal muscles are seen, and foot ones in two species. The jaws of 

 the oesophageal head are single-toothed in L. ovalis and L. emargmaia ; in 

 L. Salpjina triple-toothed. The oesophagus is very short in all ; the alimen- 

 tary canal below is constricted, except in L. Salpina, in which it is simple. 

 The ovary is globular in all; in L. Scdpina probably a cerebral ganghon (no 

 eye) exists. L. ovcdis is sometimes developed in mpiads in stagnant water. 



Dujardin has the following criticisms on the genus Lepadella : — " Wishing 

 to derive his generic characters too exclusively from the eye-specks, Ehren- 

 berg has separated all those having such specks into several genera ; consti- 

 tuting of those with two eye-points the genera Stephanops and Metopidut, 

 and of those with four red specks the genus Squamella. But we are con- 

 i-inced that these red points may be present or absent in the same species at 

 different periods of development. We believe, for instance, that the Lepadella 

 oralis and Stephanops muticus (Ehr.) are but a single species ; Lepadella 



