504 PROCEEDINGS OF THE ACADEMY OF [AugUSt, 



is a large, uearly spherical yolk-mass arouud which the larva is 

 curled, or rather into which it is pressed by the tension of the 

 egg-envelopes. Plate XXX, fig. 1 shows a larva freed from its 

 envelopes before killing so that it had straightened out; and fig. 2, 

 an older larva, similarly treated, but which had still retained much 

 of its normal position. The surface of the yolk -sphere is well sup- 

 plied witli blood-vessels, as shown in fig. 1, an antero-ventral one 

 being particularly prominent. The figures show' that there are three 

 pairs of gills present (in fig. 2 only one gill is shown on the right 

 hand, for the sake of clearness) ; and in the older larva the gills 

 are of great size, much branched, the first the smallest, the second 

 largest, lamellar and richly vasculated. The fore and hind limbs 

 are already well marked, the toes on both faintly outlined; but 

 most remarkable is the fact that the posterior limbs are larger 

 than the anterior, which might indicate that the former develop 

 first, in contradiction to what is known of other Urodelea. The 

 head, the limbs, and all the trunk region of the embryos, except 

 the end of the tail, are dorso-ventrally flattened, due undoubtedly 

 to pressure against the yolk-sphere, but become more cylindrical 

 after removal from the egg-envelopes. The head and trunk are 

 pigmented with dark-brown chromatophores, which in the trunk 

 region are arranged metamerically, while the yolk-sphere is not 

 pigmented and of a yellow color; and as the figures show, the eyes 

 are very large. A mouth was present in'^both cases, but there 

 appeared to be no sucking disks upon the lower side of the head. 

 In fig. 3 is shown a camera drawing of a section through a 

 stage somewhat younger than that of fig. 1 ; this section was made 

 through an embryo curled closely around the yolk-sphere, in such 

 a manner that the anterior region of the head, shown on the 

 upper side, is cut medially, while a portion of the bend of the 

 trunk, seen on the right-hand lower side, is cut obliquely. This 

 figure is to illustrate the relations of the intestine to the yolk-mass. 

 The mouth {Mo.) leads through the pharynx (Ph.) and oesoph- 

 agus ( CE-s.) to the stomach (St.), and posteriorly to the latter is a 

 short diverticulum (-D.). The small intestine (/ui. ) is seen to be 

 tubular in its proximal portion, but more distally to pass over 

 into the wall of the yolk-mass (Yk.). The yolk-mass of this 

 stage is seen to be composed of large yolk-cells, the boundaries of 

 which are very distinct. In this fig. 3 the relative diniensions of 



