NATURAL SCIENCES OF PHILADELPHIA. 321 



Tail with whorls of flat hexagonal scales, abruptly separated from those of 

 the sacrum above. 



Color above brown, with seven irregular undulate, transverse bars of a very 

 deep brown, between rump and nape. Below pale. 



lu. Lin. 



Total length 5 7-5 



Length from muzzle to vent 2 8-S 



" " axilla 2 4 



" " " ear 9 



" " " orbit 4 



" of hind limb 14 



Australia. Mns. Jardin des Plantes, in ex. 



This species is nearest the PI. d u v a u c e 1 i i D. and B. ; the differences may 

 be readily determined by comparison with Giinther's description in Reptiles 

 Brit. India. 



Ptenopus maculatus Gray, Proc. Zool. Soc, London, 1865, 640. 



Character genericus. — Toes with transverse series of very narrow, simple 

 plates beneath. Posterior loes all turned forwards, with a series of long pro- 

 cesses forming a fringe on each side ; posterior claws issuing from above a 

 broad paralellogrammmic lamina. No femoral pores. Ears distinct. Nos- 

 tril pierced in a single plate. Eyelids each half developed. 



This genus is near to Stenodactylus Cuv. and Spatalura Gray, but differs 

 markedly from both. The tail is not flattened and fringed as in Spatalura, 

 while the terminal plates of the toes and single nasal plates are marked 

 characters. 



As Dr. Gray referred this genus to the Agamidae I was induced to make an 

 examination of the skeleton. As a result of this, I am satisfied that it belongs 

 to the suborder of the Nyctisaura and the family Gecconidte. In evidence 

 for this I append the following characters: 1. The dentition is pleurodont. 

 2. The parietal bones are separate. 3. The vertebrai are amphiccelian. 4. 

 There is no sabarticular bone. 6. The coronoid process of the mandible is 

 not produced posteriorly. As characters of a higher or a lower significance 

 the following may be added. The angular bone is distinct, there are four ab- 

 dominal ribs, and three attached by long haemapophyses to the posterior mar- 

 gin of the xiphisternum. The dentary bone is prolonged below unusually far 

 posteriorly, i. e., to half way between the coronoid and articular processes. 



Character specificus. — Head large, slightly compressed. Muzzle short, ob- 

 tuse. Nasal plates two, forming a round disc, which is only in contact with 

 the nostral and first labial, and separated from its fellow by a granule. This 

 disc has its posterior third separated from the remainder by a suture ; the 

 nostril is in the anterior plate near the suture. Rostral not fissured, broader 

 than high. Superior labials longer than high, large, seven on each side. In- 

 ferior seven (to opposite sixth superior) narrow, longitudinal. Symphyseal 

 prominently rounded below, broader than high. No infralabials ; gulars not 

 smaller. 



Dorsal scales equal, hexagonal, flat ; nuchals minute, occipitals, frontals 

 and nasals a little larger than dorsals, flat. Caudals equal to dorsals, flat, 

 whorled. Tail vertically flattened at the end. Fingers and toes long, slender ; 

 former lengths 5 — 1 — 2 — -4 — 3 ; toes 1 — 5 — 2 — 3 — 4. Fingers not fringed ; 

 claws long, compressed, not concealed, but with a smooth basal sheath. The 

 posterior toes are entirely different, in the long fringes, terminal plates, and 

 the perfectly straight spine-like claws, which project from the middle of the 

 end of each plate ; the arrangement is a little like the body of a slender Onis- 

 cus, whence the name of the genus. The long cross-plates are not serrate, 

 but are rigid ; they are separated from the series of fringe-like scales by some 

 series of granules. The tail is slender, short, and slightly compressed. No 

 tubercles at base. Vent with a short fringe all round. 



1868.] 



