672 PROFESSOR FRANK J. COLE 



present drawings there were a few scattered nodules of hard cartilage. Again, as 

 regards the nasal capsule, which surely must be regarded as a whole and not as a 

 complex of two or more parts, we may find it consisting (and especially the lateral 

 plates) predominantly of hard cartilage (cp. fig. 1 of my first part) ; but it is coloured 

 blue in my present figure, because in these sections it consisted essentially of soft 

 cartilage with only a few nests of hard cartilage here and there (particularly in the 

 anterior portion of the lateral plates). Without going further into this question, which 

 must be discussed in a later section of the work, I may in the meantime point out that 

 the via media between Schaffer and Studnicka, i.e. that the various types of cartilage 

 found in the Cyclostomes represent modifications of a single ancestral tissue, which was 

 expressed in my first part, and which a careful perusal of Schaffer's latest paper does 

 not disturb, represents a satisfactory solution of the difficulty, always pending a 

 detailed examination of the embryogenesis of the Myxinoid skeleton. On this view, 

 Studnicka is wrong when he states that there is no real distinction between hard and 

 soft cartilage, and Schaffer is also wrong in claiming that the distinction is an 

 absolute one. Thus the hard cartilage would not necessarily pass through a soft 

 cartilage stage. It should, however, be mentioned that on p. 247 Schaffer states 

 that the pseudo-cartilage of Myxine is only a link in a long chain of tissues which 

 begins with the skeletal tissues of Invertebrates and ends with the typical cartilage of 

 higher Vertebrates. 



With regard to the pseudo-cartilage, Schaffer says (p. 247) : " Wir haben demnach 



hier ein Gewebe vor uns, welches manche Analogien mit der einfachsten Form echten 



Knorpelgewebes, wie es z. B. in den genannten Knorpeln von Ammoccetes und Myxine 



vorliegt, darbietet. Hier wie dort sehen wir verhaltnismassig voluminose Zellen, 



welche in ein Alveolenwerk diinnwandiger, membranen- oder kapselartiger 



Grundsubstanz eingeschlossen ercheinen. Die durch diesen Bau bedingten physi- 



kalischen Eigenschaften des Gewebes stimmen mit denen echten Knorpels ebenfalls 



iiberein, so dass die altere Auffassung desselben als einer Form des Zellknorpels 



verstandlich erscheint. Die genauere Untersuchung hat aber wesentliche Unterschiede 



vom echten Knorpelgewebe ergeben, so dass anderseits die Bezeichnung ' Pseudo- 



knorpel,' welche Stadelmann fur dieses Gewebe im Sesamknotchen der Achillessehne 



des Frosches aufgestellt hat, als vollkommen gerechtfertigt bezeichnet werden muss." 



He regards the envelope of the third segment of the basal plate as a perichondrium, 



although he points out that it is not a typical one. He also describes an infiltration 



of lime in the fibrous network of the pseudo-cartilage. At the friction area of the 



tendon of the copulo-glossus profundus Schaffer found in one animal a small nest of 



(apparently soft) cartilage. I have found the same thing in the tendon of the 



longitudinalis linguae, where there is no friction area. In this connection Schaffer 



says (p. 249): "Aus diesen Beobachtungen scheint mir mit Sicherheit hervorzugehen, 



dass die Zellen des blasigen Stiitzgewebes [pseudo-cartilage] auch eine etwas andre 



biologische Bedeutung besitzen als echte Knorpelzellen, oder dass wenigstens die 



