mm. Median length of the skull 56 Width across tips of horns 46 Width at base of horns 40 Width across orbits 44 Diameter of the orbit 8 Length of the orbit 15 Interorbital space 16 Length of the nostril 2 Diameter of the pineal foramen 1 Length of the teeth 1.5 Length of the horn from base 7.5 Width of horn at base 4 [Illustration: MOODIE PLATE 15 1. Dorsum of skull of Diceratosaurus punctolineatus (Cope), from the Coal Measures of Linton. Ohio. Original in the Museum at Berlin University. × 2. After Jaekel. _po_=postorbital: _fr_= frontal; _pof_=postfrontal; _j_=jugal; _la_=lacrimal; _mx_ = maxilla; _ps_="perisquamosal;" _pp_=post-parietal; _pmx_= premaxilla. 2. Ventral surface of the skull of _Diceratosaurus punctolineatus_ (Cope ), from the Coal Measures of Linton, Ohio. × 2. After Jaekel. _a_=anterior palatine vacuity; _ex_=exoccipital; _j_=jugal; _mx_=maxilla; _tr_=transverse; _pal_=palatine; _pt_=pterygoid; _pr_=prevomer; _ps_="perisquamosal;" _pv_=posterior or suborbital palatine vacuity; _ph_=parasphenoid. 3. Pectoral girdle of _Diceratosaurus punctolineatus_ (Cope), from the Coal Measures of Linton, Ohio. Original in the paleontological Museum at Berlin. × 2. After Jaekel. _cli_=inner side of clavicle; _ic_=interclavicle; _cl_=clavicle (lower side); _cle_=cleithrum. 4. (e) Cervical or anterior dorsal vertebra of _Diceratosaurus punctolineatus_ (Cope), from the Linton, Ohio, Coal Measures. _cv_=caudal vertebra shown with its cap of dermal bone; _dv_=dorsal vertebra with ribs; _x_=dermal plate on neural spine; _h_=humerus; _u_=ulna; _r_=radius. ] CHAPTER XVI. THE MICROSAURIAN FAMILY UROCORDYLIDÆ, FROM THE COAL MEASURES OF OHIO. =Family UROCORDYLIDÆ Lydekker, 1890.= Lydekker, Cat. Fossil Reptilia and Amphibia, pt. IV, p. 196, 1890. Moodie, Bull. Am. Mus. Nat. Hist., XXVI, art. XXV, p. 357, 1909. Type of the family: _Urocordylus wandesfordii_ Huxley. Locality and horizon: Coal Measures of Kilkenny, Ireland.