INPtTSOBlAT, ANIMAICTTLES. 87 



authors in their proposed classifications of Invertebrata. Thua, 

 Burmeistcr has classed them with Omsfacea ; Wiegmann, Milno 

 Edwards, Wagner, Siebold and others, with Vermes. To which of 

 these two classes of Articulata, preference is to be given, Siebold 

 observes, is not verj* questionable, for their affinities, with the 

 Crustacea, are but remote, since not only is there an absence of a 

 distinct abdominal membrane, and of sti'iped muscular fibre in Rota' 

 toria, but they present, both on their outer and inner surfaces, organs 

 of respiration. Again, the Rotatoria emerge from the egg with their 

 form perfect, and without any limbs in pairs ; whilst the Crustacea, 

 after their bii*th, undergo metamorphoses, and are furnished with 

 several pairs of extreaiiities. On the other hand, the Rotatoria 

 approach the Vermes (which include the Helminthx, Turhellara, and 

 Annelida) by their means of locomotion, their deficiency of limbs, 

 and the lining abdominal membrane, 



Mr. Gosse, from his observations of the internal structure of 

 Rotatoria, and especially owing to the presence of mandibles, maxillae^ 

 and maxillary palpi, afiu'ms that they have no connexion wdth the 

 Radiata. In this, he coLacides with all, or, almost, all naturalists, 

 who wordd place these animals among the Articulata, though with 

 which division of this class is, as we have seen, still a matter of 

 dispute. 



M. Doyere at first concurred with M. Dujardin in recognizing an 

 affinity so close with the Rotatoria as to class with them the Tardi- 

 grada ; but his subsequent researches have induced M. Doyere to 

 surrender this view, and, whilst admitting an affinity, to keep those 

 two tribes of animals distinct. 



Dujardin has remarked, " The Tardigrada constitute a passage 

 between the Systolides {Rotatoria) and the Jlelminthidcs on one side, 

 and the Annelida and Arachnidu, on the other." 



We have before had occasion to indicate the affinity between 

 Vorticellina and Rotatoria m. the wreath of cilia about the head ; as 

 also to state Dujardin's objections to receiving Chlostonotus in the 

 latter class ; these circumstances, consequently, prove the alliance of 

 the Rotatoria and Polygastrica. In some general features, likewise, 

 the two classes approach ; as, for iastance, iu the transparent sheath 

 enclosing the animal of Vaginicola, analogous to that in Floscularia 



