Vol. XXIV. No. 9.] 
l^OPULAB SCIENCE KEWS. 
139 
specimens varying in size from a diameter of two 
inches to a foot, and in color from a jellovvish to a 
reddish, are commonly met with. 
We talie this animal as a representative of the 
sub-kingdom Echinodermata, the fifth great branch 
— in the order of our examination — of the animal 
kingdom. It happens that a rather superficial 
feature of bodily structure gives the name to this 
group, namely, the spines which cover the body, 
these being fancied to resemble, in the case of some 
members of the group, (as the sea-urchins), the 
quills of the porcupine, the name of which in 
Greek is echinos. The name which Cuvier gave to 
the animals now forming this group, namely, 
Radiata, is a much better one, since the radiate 
structure of the body is a fundamental feature. 
But in Cuvier's classification this group included so 
wide a variety of animals that later systematists 
sub-divided it, making that section w hich possessed 
carbonate-of-lime skeletons, covered with spines, a 
sub-kingdom by itself, and terming it h'cliinodermata. 
In the case of the animals studied in the last two 
papers the parts of the body were readily distin- 
guished as anterior and posterior, and the aspects 
of the body as dorsal and ventral. But one is 
puzzled to know what application of these terms to 
make in the case of the st;irfish. There is obviously 
no headand-tail structure to the body, and observa- 
tion of the manner of locomotion shows that any 
one of the five divisions of the body may form the 
front end as well as another. And as to the terms 
dorsal and ventral, since thesty terms imply aspects 
correlative to antero-posterior diflerentiation, they 
do not apply to the starfish. A dilTerent nomencla- 
ture, therefore, being required for these animals, 
that agreed upon as best designating the conspicu- 
ous structural features is as follows : The central, 
undivided portion, pentagonal in shape, is the disc; 
the five radiating parts, the rays ; the more flattened 
side of the body, on which the mouth is situated, 
the oral aspect ; the opposite side, the ah-oral aspect. 
In the living starfish the oral side is always in 
contact with the surface or object to which the 
animal is allixed. If the specimen be lifted up, it 
will be seen that five rows, or bands, of soft, white, 
tubular feet radiate out from the center of the disc, 
where the mouth is situated. Tliese tube-feet are 
suckered at their extremities, are highly flexible, 
and capable of being extended and retracted. By 
alternately fixing and loosing them, and by the use 
of muscles within the rays, the animal is able to 
slowly creep about. In this way it can climb ver- 
ticle surfaces, as the piers of wharves or bridges. 
The tube-feet are, in fact, filled with water, and form 
a part of a somewhat complex system of organs, 
called the water-vascular system. On the ab-oral 
side of the body may be seen a small tubercle, 
perforated with many minute holes, through which 
water passes into this system. Nothing is more 
distinctive of the Echinodermata than this curious 
and admirable mechanism of membranous tubes 
and vesicles, which serves the functions of locomo- 
tion and grasping, and— not improbably — also that 
of respiration. 
In picking up a starfish it is often found clinging 
to some other animal, usually a mussel or snail, 
which the former is in the act of devouring alive. 
What the starfish does is to evert its stomach, and, 
in a manner, wrapping it about the soft body of its 
prey, gradually eat it away. Thus it may be said 
of the stomach of the starfish that it actually goes 
outside the body in search of food. In fact, in 
addition to its digestive function, it performs an 
office analogous to the grasping organs— as the 
mouth-parts of insects and Crustacea — of other ani- 
mals. This is a curious case of adaptation, the 
lack of one set of parts being made good by the 
extraordinary use of another member of the body. 
The facility with which the starfish thus gets at the 
mollusc body, drawing it out of the shell when once 
a hold has been secured, makes it a very damaging 
factor in the business of oyster culture. The star- 
fish gather in great numbers at the oyster-beds, and 
make much havoc in the growing crops of our 
favorite bivalves. 
A fact of biological interest about the starfish is 
its power of resisting mutilation. One, two, three, 
or four arms may be cut off,- — at least, in the case 
of a young animal, — and the creature seems to 
suffer no inconvenience from the loss. Eventually 
new rays will grow out again. This restoration 
of lost parts by a process allied to budding, or a 
kind of vegetative growth, marks the starfish as 
low in bodily organization. That interdependence 
of parts, that individualization of the organism, which 
renders mutilation precarious to life — if not quite 
destructive — in the higher animals, does not obtain 
in the starfish. 
In animals of low organization it is always inter- 
esting to observe what sense-organs they possess, 
and to consider the possibility of their having 
sensations, and thus a low order of mentality. In 
the starfish there are definite organs for receiving 
impressions of light — organs which we may call 
?yes, if we keep in mind that vision to the starfish 
is, doubtless, a very different thing from what vision 
is to us. At the tip of each of the five rays is a 
small reddish spot, and microscopic examination 
shows it to be a mass of pigmented cells, which 
adjoins a nerve-end, the trunk of which runs inward 
to unite with a nerve-ring, which surrounds the 
gullet near the mouth. The function of the pigment 
cells appears to be to absorb light, and that of the 
nerve-end to receive the impressions of light — that 
is, to play the part of the retina of the eyes of higher 
animals. So much may be safely said, but whether 
there is an attendant sensation of vision it is impos- 
sible to affirm. If so, it is certain, considering the 
simplicity of the organization of the eye, that it 
only enables the starfish to know light from dark- 
ness — not to distinguish the forms of objects. The 
membranous integument, in which the framework 
0/ carbonate-of-lime ossicles is imbedded, is sensitive 
to contact, and so constitutes an organ of touch. 
No other sense-organs are present, but it is not 
improbable that the membrane of the stomach has 
functions as an organ of the sense of taste and smell. 
Space remains only to mention other points 
of interest about the starfish: i. The alimentary 
canal, beginning with the mouth and enlarging 
into the capacious eversible stomach, is continued 
into a short intestine which opens by a small anal 
orifice on the ab-oral aspect. Thus the digestive 
canal, as in all animals above those of the hydra 
type (Coelenierata) , Is a tube running straight 
through the body. 2. There is a blood-vascular 
system, consisting of a circular tube surrounding 
the gullet, and five main radiating vessels passing 
out into the rays. The blood is a white fluid, con- 
sisting of a plasma and white corpuscles. 3. Repro- 
duction is sexual, there being five reproductive 
organs in each animal — one near the base of each 
ray. The sexual cells, when ripened, escape through 
the ducts of the organs opening on the oral aspect. 
4 In the course of its development the embryo 
passes through a stage when It is a free-swimming 
organism. This is before it has any resemblance to 
a starfish, the body having a sack-like structure, 
being in the gastriila stage of development. (See 
article on hydra, No. 2 of this series.) The passage 
of the embryo through a stage when it leads an 
active locomotive existence facilit.Ttes the distribu- 
tion of the species over wide areas. 
Union College, Schenectady, N. Y. 
[Specially Observed for Popular Science News,] 
METEOROLOGY FOR JULY, 1890. 
TEMPERATURE. 
Average Thermometer. Lowest. Highest. Range 
At 7 A. M 61.16° 
At 3 I'. M 78.06° 
At 9 p. M 67.58'' 
Whole Month . , . .' 70.60° 
Second Average . . .' 69.85° 
Last 20 Julys 
Second Average 
7' -SO' 
70.54'' 
56- 
67' 
56 
68.05° 
in iSSS. 
68.25° 
79° 
90° 
83° 
90° 
90° 
74.80° 
in 1887. 
73.SS° 
2j° 
25° 
34° 
34° 
5.<''3° 
The present July has been remarkable chiefly for 
its continued drouth. The lowest point of the mer- 
cury the last month was 56°, on the loth, and this 
was also the coolest day, with an average of 61 66°. 
The 19th and 20th were but a fraction higher. 
These three days averaged just 62". The highest 
point was 90", on the 31st, and this was also the 
warmest d.-iy, with an average of 8i". The 8th, 
i6th, and 30th were nearly as warm, the mean 
of the four days being a small fraction over So '. 
The mercury stood at 82'^' at 9 I*. M. on the Slh, but 
fell to 67" on the following morning — a fall of 15° 
in ten hours. The entire month was seven-tenths 
of a degree below the average of this month for the 
last twenty years. In only five Julys in twenty 
years has the average been below the present. The 
long, severe drouth has probably given the general 
impression of an unusually warm month, although 
actually below the average. A few days, however, 
were intensely hot, as noticed above. 
SKY. 
The face of the sky, in 93 observations, gave 48 
fair, 25 cloudy, 16 overcast, and 4 rainy, — a percent- 
age of 51.6 fair. The average fair the last twenty 
[ulys has been 609, with extremes of 41.9 in 18S9, 
and 76 3 in 1S7S, with only four Julys more cloudy 
than the present. The morning of the 14th was 
foggy. 
PRECIPITATION. 
The amount of rainfall the last month was only 
1.65 inches, and most of this (1.37 inches) fell on 
the 25th and 26th. The average amount in July the 
last twenty-two years has been 3 21 inches, with 
extremes of 1.20 in 1S8S, and 9.27 in 1S89. The 
small amount in June (1.52), with scarcely a trace 
after the 13th, caused an unusual drouth, being 
continued till the 25th of July, scarcely checked by 
throe slight showers of only .03 inch each. The 
spring rains secured a good hay crop, and the 
drouth favored a speedy and safe gathering of it, 
but scorched the naked fields and pastures as in 
a hot oven, withering small fruits and causing much 
injury. Potato fields have been destroyed, in some 
instances, and ploughed up. The small amount 
of rainfall in this vicinity on and since the 25th 
has been quite insutHcient, as yet, to restore fully 
the normal state of vegetation. Heavy showers 
have been round about us, but generally only the" 
extreme borders have reached this locality. The 
amount since January i has been 27.56 inches — a 
near average of these seven months, which has 
been 27 95, showing now a slight deficiency. 
PRESSURE. 
The average pressure the past month was 29 991 
inches, with extremes of 29.68 on the 9th, and 
31 12, at nine observations between the 22d and 
29th, — a range of .44 inch. The average for the 
last seventeen Julys has been 29.988 inches, with 
extremes of 29820 in 1884, and 29991 in 1890, — a 
range of .171 inch. The sum of the daily variations 
was 2.64 inches, giving a daily movement of .085. 
This average the last seventeen Julys has been .091, 
with extremes of .074 and .118. The largest changes 
