1895- MORPHOLOGY AT THE NATIONAL MUSEUM. 265 



limb penta-dactyle, but the number of digits may be reduced. The 

 carpus and tarsus either remain cartilaginous or are but slightly 

 ossified.' Examples: Salamandra and Amphiuma. In the Labyrintho- 

 dontia the limbs are usually pentadactyle and the pectoral shorter 

 than the pelvic. The carpus and tarsus are usually cartilaginous, and 

 in some cases three centralia can be distinguished.' Example : 

 drawing of fore-limb of Eryops. 



Skull. — ' In the Anura the skull is short and wide and the 

 mandibular articulation is thrown far back. As in other Amphibia 

 there are two occipital condyles and the basioccipital and supra- 

 occipital are small and unossified. The parietals are confluent with 

 the frontals and the palatines are set transversely to the axis of the 

 skull. Mentomeckelian bones are present in the mandible in many 

 families of the Anura.' ' Cartilage in the skull of Anura is largely 

 persistent, but ossifies to form a median sphenethmoid and a paired 

 prootic and exoccipital containing the membranous labyrinth of the 

 ear. The palato-quadrate cartilage is complete and the pterygoid, 

 which arises afe a membrane bone, invades the subjacent cartilage.' 

 The former label is illustrated by two exceedingly fine specimens of 

 the skull of Rana gtippyi, each not less than three inches across, the 

 latter by a spirit preparation of the chondrocranium and Meckel's 

 cartilage of Rana escuknta. Then follow skulls of Hyla and Alytes, 

 showing the frontoparietal fontanelle, a skull of Calyptocephalus, 

 showing the roofing-in of the supratemporal fossa, and the skull of 

 Pipa with the following description : ' The cranium is excessively 

 flattened, and contains but little cartilage. There is no spheneth- 

 moid, the quadrate is well developed and the squamosal is small.' 



' In the Urodela the parasphenoid is of large size and the 

 palatines are parallel to the axis of the skull. The quadrate is more 

 or less ossified, the quadrato-jugal is absent and the lower temporal 

 arch incomplete.' The skulls exhibited are those of Salamandya, 

 Menopoma, Amphiuma, and Siren. ' In the Apoda the skull is 

 remarkable for the completeness of its roof and the large size of the 

 bones. The chondrocranium is greatly reduced.' Example : 

 Ichthyophis. ' In the Labyrinthodontia the temporal region of the 

 skull is completely roofed over by the postorbital and supratemporal 

 bones. There are large and distinct epiotics, a parietal foramen, and 

 paired dermo-supra-occipitals. The surface also is sculptured and 

 channelled by mucous grooves.' A plaster cast of the skull of 

 Bothriccps, presenting the palatal surface, does duty here, and 

 attention is called to the cast of the skull of Loxomma, on the shelf 

 below, the parts of the dorsal surface of which are labelled. 



Visceral Skeleton. — ' In the Anura the hyoid arch is slender, 

 and confluent anteriorly with the large basi-hyo-branchial cartilage. 

 Of the four branchial arches of the tadpole the fourth persists in the 

 adult as the thyrohyal. In Pipa and Xenopiis the fused first and 

 second branchials also persist, and the thyrohyal is intimately 



