On the Pectoral Fin of Eusthonopteron. 47 L 



from C. britannkus, Verhoeff, and 0. frtsius, Verhoeff, both 

 of which are not uncommon English species. However, 

 the gonopods, which are figured by Brolemann and Verhoeff 

 {loc. cit.), are quite definite diagnostic characters, and so 

 there is no doubt about the record. Our material bears these 

 numbers :— 1379, 1380, 1381, 1382, Brade-Birks collection. 



Reference. 



(i) Brolemann, II. W., and 0. W. Verhoeff. "Mat&iaux pour 

 servir a une faune dea Myriapodea de France.'' Feuille dea 

 Jeunea Naturalistes, Sept. 1896, no. 311, pp. 214 et seq., with 10 

 text-tip's. 



XLVIII. — yote on the Pectoral Fin o/'Eu-theuopteron. 

 By Dr. Branislav Petronievics. 



The pectoral fin of Eusthonopteron was figured and described 

 for the first time by \Vhib j aves (comp. J. F. Whiteaves, 

 1889, p. 87, & pi. v. fig. 5), who-e description was improved 

 by Traquair (comp. li. H. Traquair, 1890, j). 19). Two 

 other specimens of the same tin were figured by A. S. Wood- 

 ward (1898, p. 25) and W. Patten (1912, p. 391). 



During my stay in London this year the pectoral fin in 

 the British Museum specimen P. 6796 of Fusthenopteroa, 

 figured by A. S. Wood waul (whose figure was republished 

 by E. S. Goodiich in 1902, pi. xvi. fig. 1), was somewhat 

 newly prepared by Mr. F. O. Barlow. I give here a new 

 figure of it (comp. text-fig. 1) and a brief description. 



The pectoral fin in our specimen is composed (1) of an 

 axis, (2) of preaxial radials, and (3) of postaxial processes. 



The axis consists ot four pieces. The first or basal piece is 

 situated behind the displaced cleithrum, of which the inferior 

 edge lies near to its superior edge in the specimen. It is not 

 possible to decide whether this elongated and somewhat 

 obscure bony matter is to be identified wholly with the basal 

 piece of the fin, or whether it does not comprise also the 

 coraco-scapular ossification. Should this latter be the case, 

 then the front edge of the postradial process of the basal 

 would mark the limit between the basal and coraco-scapula. 



The second piece of the axis is expanded and slightly 

 bifurcated posteriorly. The third piece is somewhat, longer 

 than the second and expanded still more posteriorly, where it 

 has not only a large poslaxial process, but is also more 

 distinctly bifurcated. 



