606 REPORT—1904. 
bands of cells at the extreme tip of the head, the resemblance to an organ (the 
frontal gland) in other tadpoles which playsa part in the process of hatching, 
and the time of its appearance, suggest that this organ is developed in Phyllo- 
medusa to assist it in escaping from the egg-membranes. 
The thyroid gland in Phyllomedusa differs in an interesting way from that of 
other tadpoles. It is more like the early thyroid of Petromyzon, as it reaches along 
the whole length of the floor of the buccal cavity, from the stomodcal membrane 
in front, to end in a sac behind projecting down to the pericardium. The anterior 
portion is not a simple groove ; the outline of the lumen forms a truncated diamond: 
. The subnotochordal rod is very conspicuous, and ends posteriorly in the 
\V fork formed by the roots of the aorta. 
[ find that the pectoral lymph-hearts in this, as in other tadpoles, appear, not 
at the metamorphosis, but at a very much earlier stage, viz., when the tadpole has 
still a solid intestine and the yolk has almost disappeared from all the other tissues. 
The wall of the lymph-heart seems to be derived from an outgrowth on the 
posterior cardinal vein. Before the valves are formed the lumen of the lymph-heart 
contains blood-corpuscles. 
The Budgett Memorial volume will include a full account of the above and 
other material (Hemisus, &c.) collected in South America and West Africa, 
2. Rejuvenation. By Cnaries Sepawick Minor, ZL.D., Se.D. 
At the meeting of the Association at Belfast the author presented an ontline 
of his theory of cellular senescence, and referred to its bearings on the problems 
of differentiation, of heredity, and of sex. In this paper he presents the comple- 
ment of this theory, namely, the theory of cellular rejuvenation, which he claims 
must be defined as the increase of the nuclear substance in proportion to the 
amount of the cell-body (protoplasm). This increase occurs during the period of 
the segmentation of the ovum, and is the immediate result of impregnation, and 
itself results in the production of rejuvenated cells, z.e., cells with very small cell- 
bodies around their nuclei. These cells and their descendants then enter upon a 
eareer of cellular senescence. It must be further pointed out that if these views 
are correct Weismann’s theories of the germ-plasm are superfluous. 
3. An Haperiment with Telegony. 
By Cuaryes Sepewick Minot, LL.D., Sc.D. 
The author experimented with females of a known race of guinea-pigs kept 
by him in stock for many years, and the colours of which were well fixed. A 
male of entirely different strain was allowed to breed with virgin does, the 
offspring having about 50 per cent. of the paternal colour. The same females 
“ were then allowed to breed by bucks of their own race. In no case was there any 
trace of the colour of the telegonous father in the second sets of offspring. 
4. The Harvard Embryological Collection. 
By Cuarxtes Sepewick Minor, LL.D., Sc.D. 
The collection belongs to the laboratory of the Harvard Medical School, and 
is intended to serve as a basis for researches in vertebrate embryology. It now 
comprises over 800 series of sections of vertebrate embryos. Each series is 
numbered, and so labelled that the number of each section in the series is readily 
determined. The collection comprises eighteen central types—namely, Amphioxus, 
Petromyzon, Squalus, Torpedo, Lepidosteus, Accipenser, Batrachus, Salvellinus, 
Necturus, Amblystoma, Rana, Lacerta, Gallus, Didelphys, Sus, Lepus, Felis, Homo, 
to which it is hoped to add Alligator, a snake, a turtle, and the sheep. Of 
each type regularly graded stages are chosen, and of each stage three series of 
