The series are long and converge backwards, 5 toes: Dicamptodon ensatus, California.
IV. The palatal teeth are arranged in a nearly straight, transverse line, or they form an angle which points slightly forwards; they are not separated by a wide median space. With 5 toes: Amblystoma. Some 16 species in North and Central America, one in Siam, p. [110].
Salamandrella keyserlingi.–The mode of propagation of this newt-like species has been observed by Shitkow near Jekaterinburg in the Ural mountains. The eggs were laid at the end of April and were deposited in bags, which were attached to a plant, with one end about an inch below the surface of the water. The bag measured 15 cm. in length and 2 cm. in width and contained 50 to 60 eggs. The larvae were hatched in 14 days in a sunny aquarium; in another with a northern aspect the hatching took 23 days. The larvae were 10 mm. long, and remarkable for the length (1 mm.) of their balancers.
Amblystoma opacum.–The general shape is very much like that of the European Spotted Salamander. The head is short and broad, the snout is rounded. The eyes are very prominent, with a black pupil and a dark-grey iris. The neck has a well-marked gular fold. The tail is thick and almost round. The hind-limbs are considerably larger than the fore-limbs. The general colour of the shiny, moist skin is a purplish-black with light grey, transverse, partly confluent bars, giving the creature a pretty appearance; the under parts are paler, bluish-grey. Total length between 3 and 4 inches, or 9 cm.
This beautiful species inhabits many of the United States east of the Rocky Mountains, from New Jersey to Florida and Texas. In the perfect state it is thoroughly terrestrial and easily kept. My specimens prefer the holes of rotten and moist, moss-covered stumps, or holes beneath stones, which they leave, at night only, in search of earthworms and insects.
A. talpoideum is closely allied, somewhat stouter and almost uniform brownish-back. According to Holbrook, "it chooses light soil in which it will bury itself in a few seconds like a mole, and there continue its course concealed from view; but its track can often be followed by the elevation produced on the surface of the soil, similar to that seen in fields infested by moles."
Fig. 21.–Egg-sac of Salamandrella schrenki. × ½. (After Shitkow.)
A. punctatum is bluish-black, with a row of roundish yellow spots on each side of the body and tail and upon the limbs.
E. A. Andrews[[53]] has made observations upon the breeding of this species. Near Baltimore the eggs are very abundant in March and even in February, in small pools in the woods, but the adults are then rarely seen. Even when small pools, but 4 feet wide and 9 inches deep, were thoroughly raked out before and after the eggs appeared, no adults were found, so that it is to be inferred that the laying takes place in the night and that the adults leave the water every day to conceal themselves under stones. One female was found moving away from a bunch of eggs early in the morning. This specimen was kept isolated, and laid many eggs, and as these developed into normal larvae, the existence of internal fertilisation was proved. Previously to the laying of the eggs white spermatophores were found in the small pools, on the dead twigs and leaves covering the bottom.