Dawson, Phil. Trans. Roy. Soc. London, 1882. pl. 11, p. 634.

Credner, Zeit. d. deutsch. geol. Gesell., 1890 (IX Theil, die Stegocephalen und Saurier).

Type: Hylonomus lyelli Dawson.

The genus Hylonomus is a very important one from a taxonomic viewpoint, since it was regarded by Dawson ([216, p. 635]) as the typical genus of the order Microsauria, the most abundant group in the Carboniferous. Unfortunately the species of the genus Hylonomus are known only from fragmentary remains. I have reproduced in [plate 9] Dawson's figures of the remains of Hylonomus as published by him in 1891.

Dawson ([216]) gave, in 1882, the following definition of the genus Hylonomus: "Form lizard-like, with the posterior limbs somewhat large in proportion to the anterior. Size, small. Mandibular and maxillary teeth numerous, small, conical, pointed. Palatal teeth minute. Abdominal scales oval."

MOODIE

[PLATE 9]

Hylonomus lyelli Dawson. 1, maxillæ and skull bones; 1a, sternal bones; 2, mandible; 3, humerus, ribs, and vertebræ; 4, posterior limb; 5, pelvis; 6, caudal vertebræ. Nearly natural size. Erect tree, Coal formation, South Joggins, Nova Scotia. Photograph by Dawson, published through the courtesy of Dr. Arthur Willey. Original in the British Museum.