ZOOLOaY AND BOTANY, MICEOSCOPY, ETC. 219 



regular or irregular, and their protoplasmic contents may likewise 

 vary. In the ectoderm the stinging-cells lie between epithelial cells, 

 while in the endoderm they are found in them. On the other hand, 

 the glandular cells seem to be of the same kind, whether found in 

 the ectoderm or endoderm. The fibrils in the gelatinous layer have 

 two forms ; nervous elements may be wanting or be but feebly repre- 

 sented ; the nerve-fibres with nuclei appear to be, in the adult, almost 

 completely confined to the boundary between the superficial and sub- 

 epithelium, or between the epithelium and gelatinous layer. The 

 endodermal ciliated cells, which have the same structure throughout 

 the stomach, vessels, and inner side of the mouth-arms, are, on the 

 genital organs, differentiated into flattened or high cylindrical 

 elements, from which the genital products are derived. 



In dealing with the sensory cells, the author directs attention to 

 processes given off from their centripetal ends, which are of some con- 

 siderable thickness, and which give off at their ends fine fibrils, which 

 may be followed for a considerable distance ; these are looked upon 

 as nerve-fibrils, and it is stated that in several cases a connection has 

 been observed between a sensory and a sub-epithelial ganglionic cell, 

 by means of such a fibre. 



The sensory cells here mentioned resemble those figured by Eimer 

 and the Hertwigs, but are distinguished by the greater length of their 

 tactile setae. Similarly, a direct connection has been observed 

 between some of the stinging-cells and ganglion- cells, and it is believed 

 that such a connection always obtains. Unlike Cyanea capillata, 

 C. annaskala has transverse folds developed on its " olfactory groove " ; 

 there are ordinarily five or six of these, and they are not very high ; 

 but it is more probable that we have here to do with a gustatory than 

 with an olfactory organ. Tufts of radiating fibres may be detected 

 passing centripetally from the marginal bodies, which, gradually 

 becoming more delicate, extend to the region of the circular muscle ; 

 here they branch frequently, and form numerous anastomoses. In the 

 young they and their ganglion- cells lie in the epithelial, but in the 

 adult they are found in the sub-epithelial layer. The nerve-fibres 

 appear to have no sheaths. The motor ganglionic cells are distin- 

 guished from those of the marginal bodies by their form, for instead 

 of being hemispherical they are stellate ; nor do they appear to have 

 that striation of the protoplasm which is to be noted in the others. 



All the muscular fibrils which were noticed belonged to the 

 ectoderm ; the smooth fibres are always radially arranged, while of 

 the others we may note an unbroken circular muscle, and 16 radial 

 lobe muscles. Like all the members of the genus, G. annaskala is 

 beautifully coloured, and the males may be distinguished from the 

 yellowish-brown females by the rosy colour of their genital glands. 



Observations on Hydrse.* — W. Marshall commences by stating 

 his belief that the green colour of Hydra viridis is not due to a 

 symbiotic process, but is a property of the polyp, and in this he 

 agrees with Prof. Ray Lankester ; of this species there appear to be 



* Zeitschr. f. Wiss. Zool., xxxvii. (1882) pp. 664-702 (1 pL). 



