23G BULLETIN 34, UNITED STATES NATIONAL MUSEUM. 



the form of the cartihiges of the larynx. The size and number of the 

 pulmouary cells vary considerably. Among Hylidse, especially those 

 species with a loud voice, they are fewer and larger than in Discoglossi- 

 dse and Scaphiopidie. The forms of the sinus, auricles, ventricle, and 

 bulbus arteriosus, the three aorta bows, of whicli the median form the 

 aorta roots, etc., appear quite identical externally in the Discoglossus, 

 Scaphiopus, and Phyllomedusa. Internally the two former present the 

 known characters of the Auura, i. e., the union of the distinct ducts of 

 the first (pulmouary) and second (aortic) aorta bows throughout much 

 of their length, the sei)arate union of the two former and continuance 

 on the left side of a high free septum of the bulbus, till they are finally 

 turned over the right division toward the right, and have a common 

 issue from the ventricle. A conic pocket valve is at the origin of the 

 bifurcation of the ductus communis of the second and third aorta bows, 

 but none in any part of the course of the pulmonary. 



The general characters of the venous system have been described on 

 page 10. The researches of Hochstetter * and Howes f have shown that 

 the cardinal veins do not disappear in all of the Salientia. Hochstet- 

 ter in fact believes "that the vena cava inferior, instead of being 

 throughout its whole extent a primarily independent vessel, is a com- 

 pound structure, the product of a fusion between alate-formod hepatic 

 vessel and one or both of the posterior cardinal veins" (Howes). In 

 Batrachia the postrenal portions only of the cardinals go to form the 

 vena cava posterior, and the prerenal portions disappear or remain as 

 azygos or hemiaz^^gos veins. Their persistence is shown to be fre- 

 quent in the DiscoglossidiB, in Bombinator (Hochstetter Howes), Alytes 

 (Howes), and Discoglossus (Howes). It is wanting in other Salientia, 

 including the Aglossa, Pelodytidoe, and Pelobatidse (Howes). 



Tbe general character of the brain in the Salientia may be gathered 

 from Plate 56. As I omitted, by an oversight, to refer to the charac- 

 ters of this region in my anatomical introduction (pp. 1-12), I introduce 

 here some remarks on its peculiarities in the Proteida, Urodela, etc., as 

 well. In the Proteida (ISTecturus, fig. 1) the thalamencephalon is ex- 

 posed by the non-production posteriorly of the i^rosencephalon. In 

 Urodela generally (Plate 40) and in Salientia it is moderately exposed ; 

 in Caiciliida', (Plate 56, fig. 3) it is generally concealed. In all the tailed 

 forms there is a large vascular " supraplexus" protruding from between 

 the hemispheres. Posterior to this the epiphysis appears; it is small 

 in all the orders. The hypophysis is on the other hand large. The cere- 

 bellum (epencephalon) is a mere commissure in the entire class. The 

 diacoelia, mesocoelia, and metacoelia are only separated by slight con- 

 strictions of their walls. The metacoelia is covered in the Salientia by 

 a triangular choroid plexus (Plate 56 j>. c). In Proteida, Urodela, and 

 Trachystomata the olfactory lobes (rhiriencephala) are distinct ; but 



*Morpliologisclies Jahrbiicb, 18S7, p. 119; Auatomischer Auzeiger, 1887, 517. 

 tProcee.l. Zool. Soc. London, 1883, p. 122. 



