(a) In water, either (1) very advanced, large-headed larvae 45 mm. long (instead of 25-30 mm.) with gills already reduced, which had awkward, embryo-like movements, and in some few days metamorphosed into small perfect salamanders; or (2) moderately advanced, properly proportioned larvae, 40-41 mm. long, provided with large gills of (at first) intrauterine character, which were reduced during aquatic life.
(b) On land, small (26 mm. long) larvae with rudimentary gills, having the body rounded instead of being flattened from above downwards, and an elongated narrow head, which were unable to live in deep water. These larvae changed to the salamander colour in 10-12 days, and after four weeks metamorphosed into salamanders 29 mm. long.
(c) In the foregoing cases the experimental conditions were not continued, or in other words, basins of water were provided in which they could spawn. But if the experimental conditions are continued, these Salamandra maculosa which were born newt-like (viz., not in a larval condition), are themselves newt-bearing from the first time they give birth, using the dry land, and bringing forth only two young, the normal number for the births of S. atra. These young are 40-41 mm. long, and are dark-coloured, resembling greatly the normal new-born S. atra.
This epitome of the observations illustrating the inheritance of acquired characters has been very widely quoted, and may not unnaturally be taken to summarize a wide experience of the modified animals. Reference to the details given in the same paper shows that, as alleged, each of the four types of behaviour enumerated was witnessed once only in the case of each of four females, no two agreeing with each other. As to the number of the males or their habits nothing is said. The first female, a (1), bore five young; the second, a (2), bore two, of which one was a partial albino; the third, b, produced four young; and the fourth, c, two as already stated.
In the case of c the details show that the female gave birth immediately after being transferred from the open-air terrarium to one indoors, which contained no basin of water. This is the example of the consequences which follow on a continuance of the experimental conditions.[17]
As regards S. atra the converse is reported. Various means were used to induce them to eject their young prematurely in water, such as massaging the sides of the mothers, or raising the temperature to 25° or 30° C., with various degrees of success. But afterwards it was found that specimens collected wild at an elevation of about 1,000 metres responded to much simpler treatment, and gave birth prematurely in water when they were kept in a large shallow basin of water not so deep but that they could everywhere touch the bottom with their feet and keep their heads above the surface. With specimens collected at higher elevations this treatment was inoperative, and the suggestion is made that S. atra at the lower confines of its habitat partakes more of the nature of maculosa than do the individuals from greater heights; for Kammerer argues that pools suitable for breeding must be more uncommon at those elevations than they are lower down.
In the earlier paper[18] Kammerer states that newly caught females of S. atra often give birth in the water, and show an undoubted preference for doing so. He describes also how he once saw several females, wild in their natural habitat, lay their young in a rain-puddle at 1,800 metres elevation, but the larvae thus born were fully formed.
When the deposition of the young as larvae has become "habitual"[19] with S. atra, three to nine larvae may be produced at one spawning period, from 35 to 45 mm. long, with gills at most 8 mm. long, and a tail-fin 2-3 mm. broad. Such larvae are generally coffee-brown, or grey (instead of black), and show other minor differences.
The summary states that when grown to maturity they become in their turn larva-bearing, and go into the water to bring forth. Their young are more than two (3 to 5 being the numbers observed) with a length of 33-40 mm. or of 21-23 mm. at birth. They are light grey, spotted (mottled with lighter and darker colour), have relatively short gills (8 to 9 mm. at most) and a broad tail-fin (3 mm. wide). At metamorphosis they are relatively long (44 mm.) and one of them had some yellow pigment.
Here again this summary is, as a matter of fact, describing the behaviour of two mothers, of which one produced three, and the other five young.