722 
the environment, under circumstances a hundred- 
fold more favorable to their survival than the young 
of a totally unprotected form, or one only partially 
protected from immediate destruction by the buoy- 
ancy of its germs or ova. 
* The natural limitations of the supply and proper 
kinds of food were also alluded to, and some of the 
early imperfections of fish embryos pointed out, some 
having an imperforate oesophagus at the time of 
hatching, so that at this time they cannot take food. 
The relative strength of the embryos of different 
species at the time of leaving the egg was also shown 
to be dissimilar in the cases of those species which do 
not protect their broods; and it was suggested that 
such absence or presence of embryonic vigor might 
have an influence in diminishing or increasing the 
chances of survival. 
The point, however, which the speaker wished 
especially to insist upon, was, that, other things being 
equal, it was probably true that the number of sur- 
vivals out of a brood of eggs stood in nearly an 
inverse proportion to the number of germs actually 
produced, and that natural or adaptive protective 
agencies tended to diminish the fecundity of a 
species, just as a want of such protective endowments 
tended to increase fertility in order, apparently, to 
compensate for the wholesale destruction of such 
germs during their early and critical stages of devel- 
opment. 
Dr. Theodore Gill, commenting upon Mr. Ryder’s 
remarks, said that the facts just reported afforded a 
broad inductive basis for the doctrine, that, in propor- 
tion as the eggs of a species of fish were protected by 
the parents, just in that proportion were the chances 
of survival of the individual young increased, and 
the number of eggs correspondingly diminished. The 
speaker thought that it was not generally understood 
that many fishes were in the habit of caring more or 
less for their young, and that this ignorance was due 
to the fact that very few of the well-known fishes of 
Europe had such habits; and our popular writers, who 
draw so largely from European literature upon such 
subjects, failed to appreciate how frequently such was 
the case with our native forms. Citing the case of 
certain marine cat-fishes which hatch their young in 
the mouth, besides others which carry their ova upon 
processes on the abdomen, the speaker desired espe- 
cially to call attention to the fact that about two- 
thirds of the sharks and rays, or elasmobranchs, were 
viviparous; the young undergoing their embryonic 
development within the body of the parent. 
Mr. E. G. Blackford of New York read a paper 
entitled ‘Is legislation necessary for the protection 
of the ocean-fisheries?’ Judging from his own ex- 
perience and observation for many years past as a 
dealer, he would hesitate regarding the expediency of 
legislative interference with the ocean-fisheries ; which 
opinion he illustrated by statistics, and concluded 
by saying that probably the only fishery-products of 
which the supply had been perceptibly diminished 
by over-fishing, during the last fifteen years, were the 
striped bass, or rock-fish, and the lobster. 
Mr. Joseph Willcox gave an account of his obser- 
SCIENCE. 
[Vou. III., No. 71. 
vations upon the sponge fauna and fisheries of the 
shallow waters of the west coast of Florida, north of 
Tampa Bay. About thirty species of fibrous, cal- 
careous, and siliceous sponges were collected by him 
in this region; and he suggested, that, in view of the 
fact that fishing for the valuable fibrous or ceratose 
sponges of commerce was becoming less remunera- 
tive, steps ought to be taken to artificially propagate 
such forms as were of economical value. 
Prof. W. O. Atwater of Middletown, Conn., gave a 
very interesting résumé of his investigations upon 
the subject of the chemical composition and nutri- 
tive value of American food-fishes and invertebrates. 
These investigations were directed to the determina- 
tion of the percentages of proteids, carbohydrates, 
water, and refuse, contained in flesh-foods of different 
kinds: the results were carefully tabulated, and afford 
important data for the determination of the relative 
values of different fishes and mollusks as compared 
with other meats. Some of the results arrived at are 
quite remarkable: for example, a hundred pounds of 
oysters were found to contain very little more proteine 
than the same weight of milk, when the waste (that 
is, the shells) of the oysters was considered in the 
analysis. When the edible portion alone was ana- 
lyzed, the nutrient matters contained in the oyster 
were found nearly in the same quantity as in codfish 
from which the head and entrails had been removed. 
The actual cost of the proteine consumed as food, it 
was shown, varied between very wide limits: for ex- 
ample, if consumed in the form of salmon early in 
the season, at one dollar per pound, the cost of proteine 
to the consumer was at the rate of five dollars and 
seventy-two cents per pound. If consumed in the 
form of the alewife, at three cents per pound, the 
actual cost of the proteine per pound was only nine- 
teen cents. The nutritive value of different fishes 
was also found to vary considerably; that is to 
say, the percentage of proteine and carbohydrates 
is variable in quantity in different species. Thus, 
the percentage of available food-materials in the 
whole flounder is only five and three-tenths per cent, 
while in fat mackerel it is twenty-four and two-tenths 
per cent. 
The presence of only a small percentage of car- 
bohydrates in fish-food was noted, in which respect 
it contrasts strongly with fat pork and beef, which are 
rich in proteine and carbohydrates, and with farina- 
ceous foods, which are poor in proteine; indicating, 
that, as an adjunct to these, fish-foods have a high 
value in all dietaries. 
Mr. Richard Rathbun presented a paper on the 
decrease in the abundance of lobsters, briefly stating 
his conclusions regarding the supposed decrease-in 
their number, based upon materials gathered from 
many sources in the interest of the tenth census, 
and still unpublished. 
The lobster-fishery, as a separate and distinct in- 
dustry, was first started about the beginning of the 
present century, on the coasts of Massachusetts and 
Connecticut, and only as late as 1840 on the coast of 
Maine, where it has since attained its greatest devel- 
opment. The vicinity of Provincetown, Cape Cod, 
