332 Dr. F. Colin on a new genus of the family of Volvocinese.- 



Finally, after Ehrenberg had, by his researches on Volvox glo- 

 hator, solved the problem in the remarkable structure of that 

 beautiful form, and declared it also, in correspondence with the 

 structure of Gonium, a colony of numerous distinct monad-like 

 animalcules combined into a polypidom, he furnished, by a 

 series of important observations on the other genera of Volvo- 

 cinece, a revision of this family which marked an epoch in the 

 knowledge of it, and even now, in spite of the varying opinions 

 as to their anatomy and systematic character, must be esteemed 

 as the profoundest and most perfect description of this group 

 (Infusionsthierchen, 49-53). His researches went to place be- 

 yond doubt the animal nature of the Volvocinea:, which, indeed, 

 had scarcely been questioned by any one up to that time. Tn 

 agreement with his general view of the Infusorial structure, the 

 Volvocinece were regarded as Infusorial Animalcules, — with rigid 

 bodies, with a mouth and many stomachs, but without intestinal 

 canal, with a nervous system and eyes, with testes, spermatic 

 vesicle and green ovules, and lastly, with one or two proboscides, 

 which in many were enclosed in a common envelope or mantle. 

 This mantle was supposed always, except in Chlarmjdomonas, Syn- 

 crypta and Gyges, to be open in front, so that the animalcules 

 could protrude themselves some distance out and subsequently 

 remove entirely, somewhat in the same way as the Rotifers Meli- 

 certa or Tubicolaria, from their sheaths. The single animalcules 

 were said to propagate independently and develope into new po- 

 lypidoms inside this mantle (/. c. p. 50). 



This idea of the structure of the Volvocinece has been almost 

 universally accepted since the appearance of Ehrenberg's great 

 work; and even those naturalists who, like Dujardin, offered 

 opposition to Ehrenberg^s doctrine, confined themselves to de- 

 nying the existence of stomachs and sexual organs to the Volvo- 

 cinece, without in other respects doubting their animal nature 

 (Hist, des Zoophytes, 307). 



In the year 1844 Von Siebold was first led, by a comparison 

 of the moving spores of Algse with the true Infusoria, to the 

 important declaration, that besides Closterium and the Bacillarise, 

 very many of the Volvocinese must be removed from the animal 

 kingdom and placed among plants, since they are destitute of the 

 principal character of animals, contractility . " Familice infusorio- 

 rum Volvocina .... plence sunt plantis inferiorum ordinum " (De 

 finibus inter regnum vegetabile et animalia constituendis, p. 13). 

 This view was established * more in detail by Von Siebold in 

 1848 in his ' Lehrbuch der vergleichenden Anatomic ' (p. 7), and 



* A form related to the Volvocinece, the genus Gonium, had already been 

 described by Tiirpin as an Alga, under the name of Pcctoralina hebraicn 

 (Mem. dc Muse'e d'Hist. nat. xvi. 1828). 



