80 ME. W. S. EOWNTEEE ON THE 



Miklucho-Maclay. — Ueber ein Schwimmblasenrudiment bei Selachiern, Jenaisehe Zeitschrift fiir 



Medicin uiul Naturwissenscli., Ed. iii. 1868, p. 448. 

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pt. iii. 

 Rkixhakdt, J. — Ueber die Scliwimmblase in der Familie Gymnotiui. Archiv fiif Naturgeschichte, 



Berlin, 1854, p. 169. 

 Sagemehl, M. — Beitriige zur vergleichcnden Anatomie der Fisclie : III. Das Cranium der Characiniden. 



Morph. Jahrb., Bd. x., 1884. 

 Sagemehl, M. — Die acccssorischen Branchialorgane von Citharimis. Morph. Jahrb , Bd. xii., 1886-7. 

 SrENCER, B. — Contributions to our Knowledge of Ceratodus : Pt. I. The Blood-vessels. Macleay 



Memorial Volume, Linn. Soc. N.S.W., 1893, p. 1. 

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Forsciiungsreiseu in Australia und dem Mahiyischen Archipel., Jena, 1898. 

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Tidsskr., Bd. xiii., 1883. 

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 WiEUERSHEiM, 11. (W. N. Pakker). — Comparative Anatomy of Vertebrates. 2ud Ed, London, 1897. 



DESCllIPTION OF THE PLATES. 



Plate 3. 



Fig. 1. Hydrocyon hrevis. General view of air-bladder and stomach. Liver removed. Stomach flexed 

 ventrally. Blind sac somewhat large. 



2. Sarcodaces odoe. General view of air-bladder and stomach. Liver removed. Stomach flexed 



dorsally. Ductus pneumaticus opens into left side of alimentary canal. Air-bladder 

 opened to show ridging. 



3. Macrodon trahira. Stomach greatly distended and flexed dorsally. Large blind sac. Orifice 



of ductus pneumaticus on the left side. 



4. Serrasahio tiumeralis. Air-bladder partly opened, showing ridging and pouching. Posterior 



sac the smaller. 



5. Lebiasina bimaculatn. Cellular air-bladder. Ductus pneumaticus opening into left side of 



alimentary canal. 



6. Erythrinus unitceniatus. Posterior sac of air-bladder opened to show rudimentary cellular 



structure. 



7. Macrodon trahira. Posterior sac of air-bladder opened to show ridging of its walls. 



8. Anacyrtus microlepis. Air-bladder partly opened to show faint ridging of posterior sac. 



Figs. 9-28 represent the dorsal aspect of the stomach in a scries of forms, with the relative position 

 of the opening of the ductus pneumaticus. 

 Fig. 9. Ichihyoborus niloticus. 



10. Alestes nurse. 



11. Salminus maxillosus. 



