Recent Researches on the Infusoria 



cised by points of the skin, which, though not exhibiting any 

 colour, are furnished with nerves corresponding in origin and 

 distribution with those which supply the coloured eyes of other 

 species. 



Lastly, he conceives that all doubt as to the nature of these 

 organs is removed on attending to the analogy which subsists 

 between them and the eyes of the Entomostraca. No one has 

 any doubt as to the nature of the organs named eyes in the 

 larger crustacea, and there is little doubt that the analogous or- 

 gans in the Entomostraca are also eyes. But these exactly cor- 

 respond in substance, colour, and position, with the supposed 

 eyes of the Rotatoria. 



He mentions a singular peculiarity which he has observed in 

 regard to the eyes of Melicerta ringens and Megalotrocha alba. 

 The young of these animals possess distinct red eyes, which are 

 not observable in the adult animals; they seem to be absorbed 

 or otherwise removed during the growth and extension of the 

 rotatory apparatus, which is very large in these animals. 



Dr Ehrenberg was no less successful in discovering the exist- 

 ence of eyes in several infusoria of the class Polygastrica. The 

 animals of this class, in which he first discovered them, belong 

 to the family of Astasiaea, and constitute the genera Euglena^ 

 Amhlyophis^ and Distigma. The first of these consists of seven 

 species, all distinguished by a single dark red eye placed on the 

 fore part of the body. They formerly belonged to the genus 

 Cercaria of Miiller, and it was in these animals that Nitsch, as 

 already mentioned, discovered the presence of eyes. The Am- 

 blyophis^ of which he knows but one species, has a large bright 

 red eye in the same position as Euglena, from which it differs, 

 in being destitute of a tail. The eyes of Distigma^ of which 

 he has discovered three species, consist of two small black points, 

 (Fig. 16. ) He next found one animal belonging to the family of 

 Kolpodea, which possesses a distinct eye, and he has formed it 

 into a separate genus, under the name of Ophryoglenajlavkans. 

 Further, in the family of Epitricha he has discovered an eye in a 

 very singular animal, which seems to have been confounded by 

 previous writers with the Volvox morum of Miiller, but which 

 Dr Ehrenberg names Eiidorina argus (elegans ?).. It is re- 

 markable that in this genus the eye is perceptible only in the 



