204 CLASS XIV. 



C. Muscular bulb at the base of arterial trunk with two spiral 

 valves or longitudinal folds. Respiration at once pulmonary and 

 branchial. 



See above, pp. 60, 75. 



SECTION V. Protopteri (Diplopnoi). 

 ORDER XI. Protopteri. 



Dorsal chord (Notochord OWEN) in place of bodies of vertebra?. 

 Skeleton partly cartilaginous, partly osseous. Pectoral and ventral 

 fins resembling subulate, flexible cirri. Body covered with cycloid 

 scales invested with epidermis. 



Family XLVI. Sireno'idei s. Pneumo'ichthyi. 



We here subjoin to the class of fishes a family of which the dis- 

 covery is very recent, and which has caused no small perplexity to 

 zoologists, inasmuch as it appeared doubtful whether it was to be 

 referred to this class or to that of reptiles. The first species known 

 was from Brasil, and was described as a reptile (1837); shortly 

 after a similar animal, but of less size and shorter body, was dis- 

 covered in Africa, and was regarded by OWEN as a fish. 



Compare Annalen des Wiener Museums der Naturgeschichte, 1837, II. Bd. 

 s. 165 170, Tab. X. (Lepidosiren paradoxa, eine neue Gattung aus der 

 Familie der Fixchahnlichen Reptilien, VON J. NATTEBEB). 



TH. L. W. BISCHOFF, Lepidosiren paradoxa, anatomisch untersucht und 

 beschrieben. Mit 7 Steindrucktafeln. Leipzig, 1840, 4to. 



Lepidosiren paradoxa. Monographic von DB J. HYBTL. Mit fiinf 

 Kupfertafeln. Prag. 1845, 4^- 



R. OWEN Description of the Lepidosiren annectens, Transactions of the 

 Linncean Society, Vol. xvn. 1840, pp. 327 361, Tab. 2327. 



W. PETEBS Ueber einen dem Lepidosiren aunectens verwandt-en Fisch von 

 Quellimane, MUELLEB'S Archiv, 1845, s. i 14, Taf. I in. 



Lepidosiren NATTERER. Two small teeth, conical, moveable in 

 intermaxillary bone; two large teeth, folded longitudinally in the 

 margin of each jaw, cohering with jaw. Body round, posteriorly 

 compressed, surrounded by dorsal and anal fin confluent at the 

 acuminate extremity. Branchial aperture vertical in front of pec- 

 toral cirrus or fin. Ventral fins abdominal, remote, resembling the 

 anterior but nearer to the lower surface of body. 



Sp. Lepidosiren paradoxa NATTEREB, 1. 1. ; from Brasil, in morasses by the 

 river Amazon; this species becomes more than 3' long. Lepidosiren 

 annectens OWEN, from Africa, first discovered in the Gambia, afterwards 



