174 Mr Henry Goodsir on a netv O-enus, 



periodical, active during digestion, at rest during the intervals of 

 that process. The same function is performed, the same force 

 is in action, and the same organ, the cell, is provided for absorp- 

 tion of alimentary matters in the embryo, and in the adult, in the 

 plant, and in the animal. The spongioles of the root, the vesicles 

 of the villus, the last layer of cells on the internal membrane 

 of the included yelk, or the cells which cover the vasa lutea of 

 the dependent yelk, and as I have satisfied myself, the cells which 

 cover the tufts of the placenta, are the parts of the organism 

 in which the alimentai'y matters first form a part of that or- 

 ganism, and undergo the first steps of the organizing process. 



Explanation of the Plate. 



Fig. 1. Protective epithelium cells from a villus in the dog. 



Fig. 2. A group of the same cells adhering by their distal extremities. 



Fig. 3. Protective epithelium cells, cast off preparatory to absorption of 

 chyle ; instead of nuclei, they present, in their interior, groups 

 of globules. 



Fig. 4. Secreting cells thrown out of the follicles of Leiberkuhn during 

 digestion. 



Fig. 5. Extremity of a villus immediately before absorption of chyle has 

 commenced. It has cast off its protective epithelium, and dis- 

 plays, when compressed, a net-work of peripheral lacteals. The 

 granular germs of the absorbing vesicles, as yet undeveloped, are 

 seen under its primary membrane. 



Fig. 6. Extremity of a villus, with its absorbent vesicles distended with 

 chyle, and the trunks of its lacteals seen through its coats. 



Fig. 7. Diagram of mucous membrane of jejunum when absorption is not 

 going on. a Protective epithelium of a villus. Secreting epi- 

 thelium of a follicle, c c c Primary membrane, with its germinal 

 spots or nuclei, d d. e Germs of absorbent vesicles. / Vessels, 

 and lacteals of villus. 



Fig. 8. Diagram of mucous membrane during digestion and absorption of 

 chyle, a A villus, turgid, erect; its protective epithelia cast off from 

 its free extremity ; its absorbent vesicles, its lacteals, and blood- 

 vessels turgid, h A follicle discharging its secreting epithelia. 



On a New Ge7ius, and on Six New Species of Crustacea, with 

 Observations on the development of the Egg, and on the 

 metamorphoses of Caligus, Carcinus, and Pagurus. By 

 Henry D. S. Goodsir, Esq., Surgeon, Anstruther. Com- 

 municated by the Author. 



SECTION I. 



On a new Genus y with descriptions of Three New Species' of Stomapoda, 

 The first species belongs to the genus Cynthia of Thomson. 



