42 



Appendices to Second Annual Report 



surface presents a series of sinuous elevations, leaving between tliem 

 irregular, oval, or circular depressions which resemble 1 crypts.' Into the 

 bases of these crypts a number of tubular glands open, and practically 

 they serve as ducts for the glands of the mucous membrane. 



The oesophagus consists of a mucous, submucous, and a muscular coat, 

 and these coats are continued on to the cardiac and pyloric sacs. 



In the herring the muscular coat consists of striped muscular fibres, 

 which are arranged more or less irregularly at the upper part ; but at the 

 lower part and downwards on the cardiac sac, until about where it opens 

 into the pyloric sac, the striped muscular fibres are disposed circularly in 

 several layers. The oesophagus is lined by cylindrical epithelium, and 

 interspersed between these are numerous goblet cells. 



PL L fig. 1, shows one of the folds of mucous membrane isolated 

 from the oesophagus. The goblet cells have small triangular cells 

 intercalated between their upper ends. The appearance of these goblet 

 cells when isolated is shown in fig. 2. They vary somewhat in shape, 

 and are charged with mucus or its progenitor niucigen. When prepared 

 with proper precautions, one can see a delicate reticulum of fibrils in 

 their interior ; while, as is usual in these cells, the nucleus, with its small 

 mass of protoplasm surrounding it, lies quite at the base of the cell. 

 Many of the cells have open mouths, and sometimes in stained specimens 

 one may see a plug of mucus projecting from the cell. The extensive 

 distribution of goblet cells in fishes was pointed out by F. E. Schulze.* 

 The lower or attached end is long and pointed, sometimes branched. 

 Sometimes the processes are very short. Various forms of these cells are 

 shown in fig. 2. 



The relation of the oesophagus to the upper part of the cardiac sac is best 

 observed by making a vertical longitudinal section through the oesophagus 

 and cardiac sac as far as the opening into the pyloric sac. The mucous 

 membrane of the oesophagus shows the sections of the folds which give rise 

 to a series of irregular sinuous depressions. The glands begin where the 

 oesophagus joins the cardiac sac. At first the gland tubes are simple 

 tubular glands, with very short tubes, several gland tubes opening into one 

 of the crypts of the mucous membrane (fig. 3), which practically act as 

 ducts for these tubes. Here and there between groups of the glands there 

 are processes of connective tissue running up between the gland tubes 

 (fig. 7). These septa are often thicker at the upper end than at the 

 lower (fig. 7). This is also shown in fig. 5, which represents a surface 

 section of the mucous membrane of the upper part of the cardiac sac ; the 

 section was made parallel with the surface of the mucous membrane. On 

 one side (a) the crypts or mouths of the gland ducts are cut across 

 horizontally, and the amount of connective tissue (stained red) between 

 them is greater than at b, which shows the sections of the actual secretory 

 parts of the gland tubes. 



The glands are simple tubular glands, with, at first, a very short 

 secreting portion. There does not appear to be any distinct membrana 

 propria, and the secreting epithelium rests directly on the fine septa of 

 connective tissue which bounds and gives form to the tubes. The tubes are 

 lined by a single layer of polygonal, more or less cubical cells, resembling 

 those in PI. II. fig. 6. The cells resemble in form and general appearance 

 the ' outer ' cells found in the gastric glands or ' glands of the fundus ' in 

 the stomach of mammals. The cells form one continuous layer, leaving 

 a small lumen. The shape and other characters of the cells are more 

 fully described under ' cardiac sac' I have failed to detect any evidence of 

 a muscularis mucosae in the mucous coat. Outside is the muscular coat, 



* Archiv f. Mik\ AnaL, vol. iii. 



