. The biology of the frog. Frogs. 238 THE BIOLOGY OF THE FROG. The first vertebra, or atlas, differs from the others in hav- ing no transverse processes, in the absence of the anterior zygapophyses, and in having in front a pair of oval, concave facets for articulating with the occipital condyles of the skull. The ninth vertebra has the transverse processes very strong and directed obliquely backward ; it has no posterior zygapophyses, and the posterior surface of the centrum bears a pair of prominences for articulation with the urostyle. The iirostyle is ele- vated on the dorsal side into a p
. The biology of the frog. Frogs. 238 THE BIOLOGY OF THE FROG. The first vertebra, or atlas, differs from the others in hav- ing no transverse processes, in the absence of the anterior zygapophyses, and in having in front a pair of oval, concave facets for articulating with the occipital condyles of the skull. The ninth vertebra has the transverse processes very strong and directed obliquely backward ; it has no posterior zygapophyses, and the posterior surface of the centrum bears a pair of prominences for articulation with the urostyle. The iirostyle is ele- vated on the dorsal side into a prominent keel which extends nearly to the posterior end. The anterior sur- face possesses a pair of cavities for articula- tion with the ninth vertebra. The verte- bral canal is small and triangular in outline. There is a pair of small openings through the sides of the urostyle near the anterior end for the exit of the last pair of spinal nerves. The centra of the vertebrae are joined together by means of pads of hyaline cartilage; connecting ligaments extend along both the ventral and the dorsal surfaces of the centra; and the arches and neural spines are joined by .ligaments. The spinal nerves make their exit through the Intervertebral foj-amina, between the sides of the neural arches. The Pectoral Girdle and Sternum. — The pectoral girdle is a bony arch which gives support to the fore limbs. The upper end of the girdle is formed by a flat, distally expanded SCygf Fig. 66.— Transverse section of shoulder girdle, cor, coracoid; , epicoracoid ; gl, gleniod cavity; hu, humerus; sop. scap- ula; , supra-scapula ; 7^. 3, third ver- tebra. (After Parker and Parker.). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Holmes, Samuel J. (Samuel Jackson), 1868-1964. New York, The Macmillan company;
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectfrogs, bookyear1906
