72 ON THE STRUCTURES AND DISTRIBUTION OF THE 



superior inner face of the inner (second) third and even fourth digits. No peculiari- 

 ties are recorded as appearing in the European species. 



Many Hylidse, — Agalychnis, Trachycephalus — develope a corneous shield on the 

 inner superior aspect of the inner metacarpal, which is prolonged on the digit. 



While no appendages of the season have been observed in some Cystignathidse, in 

 several genera two acute spurs appear on the superior aspect of the thumb, and 

 rarely spur-like tubercles on the breast ; the body is sometimes shielded with hardened 

 points on the rugosities, or the lip surrounded by an arched series of corneous rugae. 

 In one sjsecies the arms themselves increase remarkably in thickness and bulk, espe- 

 cially the brachium. 



With regard to the differences in the arrangement and structure of the internal 

 organs, a great deal remains to be observed. Henle (Anatomic des Kehlkopfes) 

 points out some inconsiderable differences in the form of the cartilages of the larynx. 

 The size and number of the pulmonary cells vary considerably. Among Hylidaj, 

 especially those species with a loud voice, they are fewer and larger than in Disco- 

 glossidge and Scaphiopodidte. The forms of the sinus, auricles, ventricle and bulbus 

 arteriosus, the three aorta bows, of which 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 Anura, i. e., the union 

 of the distinct ducts of the 1st (pulmonary) and 2d (aortic) aorta bows throughout 

 much of their length, the separate 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 form of the liver does not differ from the usual type in any of the various 

 species examined. In the alimentary canal there appears to be little variety in im- 

 portant points. The stomach has generally a more longitudinal position than among 

 Bufoniformia, except among Scaphiopodidas and in Ceratophrys, where it is equally 

 transverse. No intestinal valves were observed in Pelobates, Hyla, Phyllomedusa, 

 Ceratophrys, but a strong pyloric muscular constriction in Pleurodema, and one at 

 the extremity of the small intestine in Cystignathus p a c h y p u s . 



The testes are single in examples of all the types examined, and not strictly 

 symmetrical; they are variously situated with reference to the kidneys. Thus in 

 Ranoidea a u r e a, and Trachycephalus lichenatus they are elongate and at the 

 middle of the length of the kidneys, while in Hyla b o a n s and Scytopis v e n u 1 o - 

 s u s they are oval and one or both at the anterior extremity of the latter. In 

 Phyllomedusa scleroderma they are more than half the length of the broad 



