mm. Length of specimen, as preserved 110 Median length of the skull 24 Width across the mandibular angles 25 Greatest width of skull 30 Length of vertebral column from occiput to sacral region 80 Length of left humerus 19 Width of distal end of left humerus 5.5 Length of radius and ulna 11.5 Width of distal end of radius 2 Length of digit II, as preserved 16 Length of digit III, as preserved 14 Length of femur 24 Width of distal end of femur 4 Length of tibia 18 [Footnote B: The type specimen was collected in 1857 by Dr. John V. Lauderdale, who presented it to Dr. J. S. Newberry.] CHAPTER XII. SUBCLASS LEPOSPONDYLIA ZITTEL, 1887. COAL MEASURES TO PERMIAN. (Europe and North America.) The group is here defined according to the English edition of Zittel's Text Book of Paleontology, 1902, p. 125. "Notochord persistent and enclosed in constricted bony cylinders, hour-glass-shaped in longitudinal section. Teeth simple, conical, hollow." According to Zittel there are two families, the Microsauridæ and the Aistopodidæ. The latter family is dealt with under _Aistopoda_ (p. 76) and it is there shown that the group is in no wise a valid one. The former family is regarded as an order and is fully entitled to that rank. As defined here the subclass _Lepospondylia_ contains but a single order, the _Microsauria_. Extinct, terrestrial, aquatic, or semi-aquatic amphibians; skull pitted and grooved by lateral-line canals and by sculpturing marks, or the skull may be smooth; teeth present on most of the palate bones; exoccipitals cartilaginous or calcified, never completely osseous; sclerotic plates sometimes present; skull of various shapes. Vertebræ with notochord largely persistent, hour-glass-shaped; neural spines low or high, or absent; ribs intercentral and single-headed, with an incipient tubercle in some forms; vertebral column differentiated into dorsal and caudal series; cervical series not clearly defined. Limb bones with well-ossified perichondrium, endochondrium partly ossified; epiphyses absent; carpus and tarsus (tarsus osseous in two species) cartilaginous; phalanges clawed or not; digits 4 in hand and 5 in foot. Pubis sometimes calcified but never osseous. Definition of the Order Microsauria Dawson, 1863. Coal Measures And Permian. (Europe and North America.)