468 HENRY C. TRACY 



and Gadidae) through forms like Hyodon and Notopterus, up to 

 the highly elaborated mechanism in Clupeidae. But, unfortu- 

 nately, Tysowski's morphological conceptions are quite incon- 

 sistent with well-known facts regarding the bony structure of 

 the clupeoid skull, concerning which there is no essential disa- 

 greement on the part of other investigators. 



In support of his theory, he uses the following argument. 



Auf Grund meiner Befunde wlirde es mir schwer fallen, die Bullae 

 osseae anteriores als ein Erzeugnis der Prootica anzusehen, da ich 

 Prootica, ahnlich wie Opisthotica, infolge der breiteren Gestaltung des 

 Basioccipitale und Basisphenoideum mehr nach aussen liegend, wie 

 gewohnlich mit der vorderen und ausseren Ampulle und dem ausseren 

 Bogengang in Beziehung treten sehe, tibrigens lasst auch die starke 

 Ausbildung des Corpus basisphenoidei vermiiten, dass er von den 

 Knochenlamellen der Prootic nicht iiberbriickt sein kann und die 

 kapselartigen Gebilde eher ihm den Prootic angehoren. 



The relation of these bones to each other and the location of 

 the bony capsules I have demonstrated to be quite different 

 from the relations as Tysowski conceives them. That the 

 anterior osseus capsule, in its entirety, is a part of the prootic 

 bone in the adult cannot be questioned. It has been so described 

 by all writers on the subject; my own preparations also demon- 

 strate it. The general relations of the fifth and seventh nerve 

 complex to the capsule and to the bone in which it lies are the 

 same as the relation of these nerves to the prootic in the typical 

 teleost cranium. 



In investigating these relations I made use of dried preparations 

 of the skull, as well as freshly cleaned specimens cleared in xylol, 

 some of which are stained with alizarin, to bring out the cartilage 

 lines of articulation. Specimens prepared by the latter method 

 were particularly satisfactory when examined under the binocular 

 microscope by transmitted light. The lines of demarkation of 

 the bony elements were so clearly visible as to leave no room for 

 doubt as to their identity. My results agree with the descriptions 

 of the clupeoid skull as given by previous workers on the subject 

 and are also consistent with the osteological relations of other 

 teleostean groups as described by Sagemehl ('91), Allis ('97), 

 Brooks ('84), and others. In view of these considerations, it 



