124 Mr. Gr. A. Boulenger on Hymenochims. 



Fronto-parietals fused to a single bone. 



Single ostium pharyngium. 



No distinct mento-meckelians. 



Sacral diapophyses extremely dilated and fused with the 

 urostyle. 



Vertebra? opisthocoelous. 

 Characters in common with Pipa : — 



Fusion of the first and second vertebrge. 



Coracoids much expanded towards tlie sternal end. 



Very strong wing-like expansion of the ilia. 

 Characters in common with Xenopus : — 



Sternal cartilage not embraced by, extending outwards 

 beyond, the epicoracoid cartilages. 



Long thyrohyals. 

 Hymenochiriis stands by itself in the presence of only 5 

 pra?sacral vertebvEe ; the second and third diapophyses are 

 very long and subequal, but not so long and not so strongly 

 directed forwards as in Pipa and Xenopus; the first, fourth, 

 and fifth are shorter and also subequal. Fronto-parietal 

 very broad, measuring half the width of the skull. Thyro- 

 hyals extremely long. Tibio-fibula with a wing-like ex- 

 pansion of thin bone on each side, forming a deep groove on 

 the outer side; the two bones of the tarsus united by similar 

 bony expansion, which projects wing-like on each side. 

 Pelodytes was so far the only Batrachian in which a fusion 

 of the astragalus with the calcaneum was known to occur, 

 and tliis in a very different manner. The prgecoracoids are 

 feebly curved and form a nearly straight transverse bar, 

 instead of an angle directed forwards. 



Having thus indicated the most salient osteological features 

 of Hymenochirus Boettgeri^ I pass on to a description of the 

 external characters. 



Head small, very strongly flattened, a little broader than 

 long; snout rounded, projecting slightly beyond the mouth; 

 nostrils terminal, directed upwards and forwards ; eyes small, 

 without lids, supero-lateral ; pupil round; interorbital space 

 about half the width of the head ; no tympanum. Body 

 much depressed, twice and one third ( (5" ) to thrice (?) as 

 long as the head. Fore limb rather feeble ; fingers moderately 

 elongate, sharply pointed, one-half or two-thirds webbed, first 

 a little shorter than second, third longest ; no carpal or sub- 

 articular tubercles. Hind limb strong ; tibio-tarsal articu- 

 lation reaching the eye or between the shoulder and the eye; 

 tibia two fifths to one half length of head and body; toes 

 broadly webbed, but not to the tips, which are sharply 

 pointed, the inner three armed with a small black claw j third 



