ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 235 



could not satisfy himself as to tlie ectodermal origin of the nervous 

 system. The enteric epithelium is formed of cells which are filled 

 with a finely granular protoplasm, or small masses of fat-drops. 

 These appear to owe their origin to the breaking-up of the yolk-cells, 

 and it is in this region only that the cells have fatty contents. The 

 author cannot agree with his predecessor in thinking that the yolk- 

 cells are transformed into the epithelial cells of the intestine ; he 

 finds, rather, that these yolk-cells lose their individuality and become 

 transformed into irregular masses, while no trace is left of their 

 nuclei. 



Rotatoria of Giessen.* — K. Eckstein commences with a review 

 of the genera and an account of the fifty species of Eotatoria found in 

 the neighbourhood of Giessen. 



Treating of Floscularia appendiculata he discusses the question 

 whether the long cilia are stiff and immobile, or whether they form 

 currents which carry the food to the mouth, as in other Rotifers. 

 Although never able to observe that the cilia act as described by 

 Ehrenberg, he has been able to convince himself that they are capable 

 of voluntary movements and react to external stimuli. The long, thin, 

 finger-like process which lies among them has probably a sensory 

 function. No distinct ganglion could be detected, but sensory organs 

 were obviously represented by a process on the dorsal surface, lying 

 just behind the wheel-organ, which carried a tuft of setae. Two red 

 eye-spots were seen at the margin of the orifice, when the animal was 

 in a contracted condition. In the young the wheel-organ consists of a 

 circlet of not verj long cilia placed on the edge of the oral funnel. 

 In Ptygura melicerta the foot is provided with large glands, by the 

 secretion of which the animal is able to attach itself to water-plants ; 

 its blood-corpuscles are of a comparatively large size. Philodina 

 roseola is to be distinguished from P. citrina by the regular distribution 

 of its coloration, which is not absent from the first and last joints as 

 in the other. In most of his specimens of Moiifer vulgaris Eckstein 

 was able to recognize a lens in the eye ; in many cases he found 

 that one or both eyes were divided into two or three, or even into 

 ten or twelve, red corpuscles. In addition to the cephalic ganglion 

 there were detected a large spindle-shaped cell, lying on either side 

 of the rectum, and exactly comparable to the nerve-cells found by 

 Leydig in Lacinularia socialis. In Notommata aurita the ganglion 

 consists of two layers, of which the inner is homogeneous and the outer 

 granular. The mode of locomotion of N. lacinulata is described, as 

 are the voracious habits of Eosphora lacinulata, the differential cha- 

 racters of which, as compared with Triophthalmus dorsalis are pointed 

 out, and it is shown that the latter is not the young of the former. The 

 tail of Scaridium longicaudatum is of great assistance in the execution 

 of rapid movements. Diurella rattulus swims about with its dorsal 

 surface downwards and executes with it movements to the right and 

 left, while the head and tail form fixed points. 



In Monostyla lunaris fixed points are obtained by the better deve- 



* Zeitschr. f. Wiss. Zool., xxxix. (1883) pp. 343-443 (6 pis.). 



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