176 



ducts being present. In longitudinal sections niost of the secondary 

 ducts are cut obliquely, very few transversely, showing that most of 

 them must take a longitudinal direction. 



Sanfelice (9) also examined sections of the appendix digitiformis 

 of Torpedo narce and he states that here the main central duct is 

 lined with low cylindrical epithelium as well as the secondary ones 

 and also the tubules. Consequently these various ducts can in Torpedo 

 narce only be distinguished one from another by the size of the lumen 

 contained. He also states that there is in Torpedo a quantity of 

 connective tissue between the tubules. 



Thus the appendix digitiformis has obviously a compound tubular 

 structure and would seem to resemble somewhat closely the compound 

 pyloric appendage of Acipenser and Lepidosteus described by Mac- 



ALLUM (8). 



The absence of lymphatic tissue in the appendix makes its histo- 

 logical structure appear very different from that of the vermiform 

 appendix to which it was compared by Howes (6), However we 

 hardly expect to find such tissue in Elasmobranchs since Berry (1) 

 has stated that the skate contains no lymphoid tissue and has pointed 

 out that this tissue is probably unnecessary in cold blooded animals. 



I cannot agree with Crav^^ford that the cells of the tubules re- 

 semble kidney cells — they would seem to have rather a secretory or 

 absorptive function or probably both of these functions. An excretory 

 function too would surely be unlikely in an organ which is undoubt- 

 edly endodermal in origin, Blanchard (2) and Sanfelice (9) both 

 having described the appendix digitiformis as arising from an out- 

 growth of the intestine rather late in the course of development. 



Chemical. 



In conjunction with Miss Cyriax, late of the Chemical Depart- 

 ment of Bedford College, I repeated the examination of the chemical 

 properties of the secretion which is stated by Dr. Noel Paton (4) to 

 contain a considerable amount of urea. 



We preserved nineteen glands in absolute alcohol; these were minced 

 and pounded in an agate mortar and then well shaken up again with 

 the alcohol and filtered. The filtrate when evaporated on a water 

 bath left a yellow residue. This was then tested for urea which is 

 readily soluble in water and alcohol. The effervescence obtained with 

 an alkaline solution of sodium hypobromite was so fine as to be hardly 

 perceptible. Further when a solution was evaporated and oxalic acid 

 added during the process the white crystals obtained were apparently 



