ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 39 



of the anterior buccal cavity, and the buccal musculature. Of tbe 

 first of these there are no less than thirteen on each side, and, as it 

 would seem, their function is mixed. There are the same number of 

 nerves for the cephalic lobes, and they anastomose largely with one 

 another. The third group supply the gustatory bulbs, among other 

 structures. The commissures of the anterior visceral ganglia arise 

 from the lower half of the oesophageal ring, and there is also a 

 ganglion for the " subradular organ." After a detailed description of 

 other parts of this system, which would be of interest only to those 

 acquainted with the work of v. Ihering and Hubrecht, the author 

 passes to the nervous supply of the heart and peritoneum. If pieces 

 of fresh tissue from the auricle are placed in sea-water and then ex- 

 amined, large yellow pyriform cells may be seen between the muscular 

 plexus of the heart. An aid to study was found in the use of a 

 mixture of glycerine with a little acetic acid and water ; the nerve- 

 cells were then seen to have a very large nucleus and a distinct 

 nucleolus ; they are generally oval, and always have a protoplasmic 

 process ; they are placed between the epithelial investment and the 

 musculature of the heart, where they form a fine nerve-plexus of 

 small multipolar and large bipolar cells. Observations on the peri- 

 toneum appear to indicate the presence in it of bodies which are, 

 physiologically, comparable to the Pacinian bodies of the Vertebrata. 

 In an account of the digestive apparatus, attention is directed to 

 extremely delicate unilobular buccal glands, which are formed on its 

 upper surface, and are not very easy to detect. Glands, to which the 

 name of " sugar-glands " is applied, were found to open into the 

 oesophagus, and to have a truly embryonic form, for they were simple 

 outpushings of the enteric wall, with a single large lumen; the 

 wall of the gland is remarkable on account of the development of villi 

 on it. Variations in the colour of these parts are to be detected, and 

 it appears that in the course of secretion the green colour is converted 

 into violet, or, in other words, before the metabolic changes in the 

 gland-cells can be effected, a chemical process is gone through, which 

 finds visual expression in the alteration of colour. Another pecu- 

 liarity is to be found in the fact that the secretory vesicles are not 

 formed within the cell, but are excreted from it, without being visible, 

 as such, within it. No definite information can be given as to the 

 function of these glands. The epithelium of the stomach is distin- 

 guished from that of the oesophagus by the absence of cilia ; into it 

 there open, by separate orifices, the ducts of the liver, which consist 

 of two unequal portions ; the larger and lower portion, or that 

 which primitively lies on the right side, is a large acinous gland, in 

 which foui' several lobes can be made out. The most primitive 

 arrangements possible are to be seen in the Chitons, for there are 

 none of the longer efferent ducts, but the liver opens directly into the 

 stomach ; the lower wall of the upper portion of the stomach forms 

 an infundibular invagination, and is gradually continued into the 

 wall of the primary lumen of the liver ; the orifice itself is not 

 wide ; the high epithelium of the stomach gradually disappears, and 

 four or five circular folds appear in the infundibulum. Attention 



