334 PKOFESSOR FRANK J. COLE 



from the nucleus, the contents of the cell vary considerably, not only in appearance but in 

 staining reactions. Sometimes we can distinguish intra-cellular bodies of two kinds, which 

 may, however, both occur in the same cell. First, there are large waxy bodies, which 

 vary in consistency, and lie in a clear area or vacuole. In their early (?) stages these 

 stain faintly with eosin and iron hajmatoxylin. Then there are the smaller spherical 

 bodies, which may be very numerous and variable in size, and appear to resemble the 

 zymogen granules of other secreting cells. They stain intensely with iron hsematoxylin 

 and eosin. The former have been described by Schaffer, but they are not invariably 

 present, whilst the latter he does not mention. In some cases where these two intra- 

 cellular products are extremely developed, the nuclei are indistinct, and only stain 

 faintly. There are many indications that the larger intra-cellular bodies are formed by 

 the fusion of the smaller ones. 



When there is a single large intra-cellular product present it lies, as a rule, either on 

 the peripheral or the central side of the nucleus. Schaffer states that it occurs only 

 rarely at the peripheral end of the cell, but this statement appears to be based on the 

 examination of an insufficient number of individuals, since it may be found more often 

 peripherally than centrally, and in some cases I have found it almost exclusively on 

 the outer side. In a few cases there are two products in one cell, which may be either 

 together central or external to the nucleus, or separated, with the nucleus crushed 

 between them. These products in isolated cases may be extruded bodily from the 

 cell into the cavity of the vesicle. 



Schaffer figures one condition which I have not seen, although I do not on that 

 account question the accuracy of his observation. Here the nucleus is pushed to the 

 periphery of the cell, and is greatly compressed from side to side so as to assume a rod- 

 like form, whilst the central portion of the cell is occupied by a large, oval, feebly 

 staining secretion product, surrounded by a sheath or " theca." 



The contents of the vesicles are again very variable. Usually they appear quite 

 empty in the sections. Occasionally one finds a coagulated substance of a granular 

 appearance, and only very rarely, as Schaffer also finds, is there present the colloidal 

 substance so characteristic of the thyroid vesicles of higher vertebrates. 



The thyroid of Myxine was first described by W. Muller in 1871 (43) in the 

 following words : " Dagegen ist mir der Nachweis des Organs in der Classe der Cyklosto- 

 men bei Myxine glutinosa gelungen, welcher die Schilddriise bisher allgemein abge- 

 sprochen worden ist. Sie liegt hier in der fettreichen Bindegewebslamelle, welche sich 

 von der Ventralfiache des (Esophagus zur oberen Flache des Kiemenarterienstammes in 

 dessen ganzer Ausdehnung erstreckt und besteht aus einer ziemlich betrachtlichen Zahl 

 theils zerstreut liegender isolirter, theils zu kleinen Gruppen von 2-5 vereinigter rings 

 geschlossener Follikel, Letztere sind theils von kugeliger, theils von ellipsoidischer 

 Gestalt, der Durchmesser der ersteren schwankt zwischen 0,1 und 0,25 der Liingen- 

 durchmesser dur letzteren erhebt sich bis zu 0,4. Sie bestehen aus einer dlinnen Mem- 

 brana propria und dieser aufsitzendem einschichtigem Epithel. Die Zellen des letzteren 



