406 ANNUAL OP SCIENTIFIC DISCOVERY. 



still present a considerable range. By most species the eggs arc deposited 

 in the water cither upon aquatic plants or on the bottoms; by others, as in 

 Salamandra erylhronotit, they arc laid in damp places under logs or stones; 

 with some the evolution of the embryo commences a short time previous to 

 the laying of the egg, and is completed subsequently, while there are other 

 species which are wholly viviparous. 



The most remarkable deviations from the ordinary modes are to be found 

 in those instances in which the eggs, after being laid, are brought into a 

 more or less intimate relation with the parent, as in the " Swamp toads " 

 (Pipa Americana) of Guiana, where each ovum is deposited in a sac by itself 

 on the back of the female; in Nolodelpliys of Venezuela, where all the eggs are 

 lodged in one large sac, also on the back, and is analogous to the pouch of 

 the Marsupials, and in Alytes, the "Obstetric toad " of Europe, where the 

 eggs are wound in strings around the legs of the male, who takes care of 

 them until they hatch. 



The species, the habits of which are noticed, below, and which, in so far 

 as I have been able to learn, have not attracted the attention of naturalists, 

 adds another to the series just mentioned, though the relation of the foetus to 

 the parent becomes less intimate than in any of the preceding cases. 



Hylodes lincatus (Dum. and Bib.) is very common in Dutch Guiana, and its 

 peculiar habits are well known to the colonists. 



In the month of May, 1857, during an excursion to the country inhabited 

 by the Bush negroes, above Sara Creek on the upper Surinam River, 1 had 

 an opportunity, for the first time, of seeing these animals carrying their 

 young, and subsequently collected several specimens. In one instance the 

 larvae were retained permanently adherent to the back of the parent, in con- 

 sequence of the coagulation of the mucus covering the surface of the body, 

 and are still preserved in the Academy of Comparative Anatomy at Cam- 

 bridge. The young, from twelve to twenty in number, were also collected 

 upon the back of the mother, their heads directed towards the middle line. 

 They were about three-fourths of an inch in length. No limbs were devel- 

 oped, and no special organ was found to aid them in adhering to the back 

 of the parent. The adhesion may have been effected by the mouth ; and 

 this is rendered probable by the fact that all of them had the month in con- 

 tact, either with the skin of the parent or with that of another larva. A 

 viscid mucus covering the integuments, undoubtedly assisted in some meas- 

 ure to bring about the same results. However this may be, they retained 

 their places perfectly well, and were not displaced when the mother, closely 

 pursued, carried them through the grass. 



On dissection of the young, nothing was found matei'ially different to condi- 

 tions of the larva? of other anousa. Gills had disappeared, but were replaced 

 by internal ones, which were arranged as usual on three hyoid arches. The 

 development of the lungs had commenced, and these were represented by a 

 slender conical mass of "cells, but not permeable to air. The mouth was 

 provided with finely denticulated horny jaws, and the intestinal canal was 

 shorter and less spirally convoluted than in ordinary larva? of frogs and 

 toads. The stomach was not so much developed as to be distinguished 

 from the rest of the intestine; but this last, after passing the liver, was 

 somewhat dilated, and contained, as was shown by the microscope, large 

 quantities of yolk-cells, which had not been absorbed, and which were 

 adherent to its walls. 



Vf e have here, then, a larva, in all the details of its structure, especially in 



