PHARYNGEAL GLAND OF THE EARTHWORM a7 
During my research on Pollenia rudis, a Calliphorine 
fly, the larvae of which live as parasites n Allolobophora 
chlorotica, I often had occasion to study sections of the 
pharyngeal bulb of several species of earthworms, and I always 
believed that I was dealing with a salivary gland as described by 
Hisen. The recent paper of Stephenson came therefore as a 
surprise to me. It mduced me to re-examine more closely my 
previous sections, and to prepare fresh ones, using this time 
special methods, which, as we shall see further on, enable us to 
solve finally the questions as to the nature, and, consequently, 
the functions of the deeply-staiming cell-ageregates. 
This seems to me to be very important, for two reasons : 
(1) the pharyngeal bulb is an organ of conspicuous size and 
appears to exist in all earthworms, and (2) the common earth- 
worm being generally used as a type for the purpose of class 
dissection, it 1s very necessary that all observations concern- 
ing its anatomy should be accurate, in order to avoid a wide 
dissemination of erroneous information. 
2. MarertaL AND MrEruops. 
The earthworms used for this study comprise three species : 
Allolobophora chlorotica Sav., Allolobophora 
foetida Hisen, and Lumbricus sp. For the study 
of the general structure of the pharyngeal bulb I used as 
fixatives: Bouin and Schaudinn with 3 per cent. of acetic 
acid, followed by staining in P. Mayer’s Haemalum or Glychae- 
malum with Eosin or Orange, or in Magenta-red and Piecro- 
Indigo-carmine. For the more delicate structures of the 
gland and pharyngeal epithelium small pieces were fixed in 
Champy’s chromo-osmic solution and stained with Iron 
Haematoxylin and Hosin. The protoplasmic inclusions were 
examined in sections prepared by Champy’s (1911) method 
(fixation in Champy’s solution, post-chromization with potas- 
sium bichromate, and staining in Iron Haematoxylin). 
For the study of the glandular secretion, which I naturally 
supposed to be mucin, I had to apply several methods. Since 
Langley’s important research on salivary glands and _ their 
