V22 tUOF. T. W. BEIDGE OIs- THE [Juiie 15, 



wbich had shown many small tubercular ulcers. The spleen and 

 lungs, and especially the glands of the mesentery, were also infected. 



Mr. Oldfield Thomas, F.Z.S., gave an account of the Mammals 

 obtained by Mr. John Whitehead during his recent expedition 

 to the Philippines, and read some field-notes upon them by the 

 collector. 



This memoir will be printed in the Society's ' Transactions.' 



The following papers were read : — 



1. On the Presence of Ribs in Polyodon (Spatularia) folium. 

 By Prof. T. W. Bridge, D.Sc., F.Z.S. 



[Received May 21, 1897.] 



The ordinary text-book and other references to the presence or 

 absence of costal elements in the skeleton of this Chondrostean 

 Ganoid leave much to be desired on the score of precision, and not 

 infrequently are diametrically opposed one to another on matters 

 of fact. 



Thus, for example, in that excellent store-house of zootomical 

 knowledge, the ' Handbuch der Anatomie der Wirbelthiere ' of 

 Stannius (Aufi. 2, 1854, " Die Fische") there occurs the following 

 passage : — " In den wesentlichsteu Verhiiltnissen zeigt Spatularia 

 sich iibereinstimmend mit Accipenser ; nur fehlen die Eippen, 

 oder werden vielmehr durch ligameutose Strange vertreten, die an 

 der Basis knorpelige Elemente enthalten " (p. 21). Subsequently, 

 in a footnote (p. 31) it is stated, "Harte E-ippeu fehlen bei Spalu- 

 laria." 



On the other hand, Giinther (' The Study of Fishes,' 1880), in 

 referring to the skeleton of the Ganoids, remarks :—"E.ibs are 

 present in most, but replaced by ligaments in Polyodon " (p. 75). 



Again, Wiedersheim, in his ' Comparative Anatomy of Verte- 

 brates ' (English translation by Newton Parker, 1886), says, "The 

 ribs of fishes show a very primitive coudition usually extending 

 along the whole length of the vertebral column (Lophobranchii, 

 Spatularia) " {I. c. p. 48). In the same work a figure representing a 

 lateral view of a portion of the vertebral column of Poli/odon is given 

 (J. c. fig. 21, p. 35), but no costal elements are indicated. The same 

 author, in his larger treatise, ' Lehrbucb der vergleichenden Ana- 

 tomie der Wirbelthiei'e ' (1886), referring to the same point, 

 remarks : — " Bei Knochenfischen, z. B. bei Lophobranchiern, sowie 

 auch bei Ganoiden {Spatidaria), kcinnen die Rippen vollstandig 

 fehlen " {I. c. p. 80). 



Finally, Vogt and Yung, in their ' Lehrbuch der praktischen 

 vergleiclienden Anatomie ' (1889-94), refer to the absence of ribs in 

 Chinuera, many Bays, the Lophobranchii, and Spatidaria (Bd. ii. 

 p. 534). 



