560 
to several times their original length. 
stone quartz 
while sericite 
planes. The 
In the same sand- 
pebbles have been pulled out and flattened, 
has been largely developed along the cleavage 
pressure can be shown to have been directed 
mainly from the south-east. (2) The second locality is 
in the midst of the Laurentian area of Buck’s County, and 
is known as Van Artsdalen’s Quarry. A mass of crystalline 
limestone is here mingled with an eruptive diorite in such 
manner as to show that it had actually flowed like an igneous 
rock, and had caught up inclusions. The results of extreme 
metamorphism are exhibited in the development in the lime- 
stone of graphite, wollastonite, and other minerals. The 
chemical changes and interchange of elements which might 
result from a loosening of molecular combinations under extreme 
pressure and their subsequent ‘‘ regulation” into new compounds 
were discussed as among the phenomena of mechanical meta- 
morphism. (3) As an American instance of the conversion of 
an intrusive diabase dyke into amphibolite schist, analogous to 
the case recently described by Teall, a long narrow belt of 
sphene-bearing amphibolite schist in the City of Philadelphia 
was adduced. This belt with distinctive mineralogical cha- 
racters cuts across the metamorphic mica schists of the region 
unconformably, and is believed by the author to be a highly 
metamorphosed intrusive dyke of Lower Silurian age. The 
original augite or diallage has been completely converted into 
fibrous hornblende, and the influence of pressure is shown in the 
perfectly laminated character of the schist in the close foldings 
produced, and in the minute structure of the rock. Some 
interesting details of the latter having been photographed, 
diagrams constructed from these were exhibited. These showed 
that the rock was traversed by a parallel series of slips and 
crushings, and that about such lines of faulting and crushing 
there was a peculiar arrangement of the lines of hornblende 
crystals, not very unlike the arrangement of iron filings about 
the poles of a magnet, such as could not be satisfactorily 
explained by any theory of aqueous deposition, but pointed to a 
lamination by pressure. 
SECTION D—BroLocy 
On the Cause of the extreme Dissimilarity between the Faunas 
of the Red Sea and Mediterranean notwithstanding their recent 
connection, by Prof. Edward Hull, LL.D., F.R.S.—The faunas 
of the Mediterranean and of the Red Sea are so unlike that if 
the beds of the two seas were upraised, and their contents ex- 
amined, naturalists would probably refer them to distinct geologi- 
cal periods. The dissimilarity is greater than was formerly sup- 
posed. In Woodward's ‘‘ Manual of the Mollusca” it is stated 
that seventy-four species of mollusks are common to the two 
seas, but Prof. Issel, of Genoa, places the number at eighteen, 
or about 2 per cent. Equal differences exist if we compare 
other great groups of life; in fact, as Prof. Haeckel well ob- 
serves, the fauna of the Red Sea is related to that of the Indian 
Ocean, the fauna of the Mediterranean to that of the Atlantic. 
This extreme dissimilarity would not surprise us if it were not 
for the proofs of recent connection between the two seas. Evi- 
dence of old sea margins, up to about 220 feet above the present 
sea-level, are frequently found along the Nile and in the valleys 
and plains of Philistria. As many of the marine forms found 
in these deposits still exist, the date of the submergence may be 
safely referred to that of the Pliocene; but it continued to a 
later period, and (in the author’s opinion) it to some extent re- 
mained to the time of the Pharaohs. The existing fauna prob- 
ably date; back to Eocene times, when the ocean spread widely 
over the area in question. In the Miocene period the main out- 
lines of land and sea as we now find them were marked out, the 
deposits of this age being here small and local. Under the ex- 
tremely different conditions existing in the two areas, the fauna 
during and after the Miocene period became differentiated. The 
connection re-established during and after the Pliocene period 
was insufficient to destroy these differences, although it allowed 
a mingling of forms to some extent. The maximum submergence 
was about 220 feet; but as the summit level between the two 
seas is about 50 feet, the depth of water would only be about 
170 feet at the maximum. Only littoral and shallow-water 
forms would cross in the adult state ; but many forms inhabiting 
deeper water in the adult state might have crossed when in the 
free-swimming larval state. When the land again rose, and the 
marine straits were finally effaced, the different physical condi- 
tions of the two seas would again come into effect. The difference 
NATURE 
[Oct. 8, 1885 
of temperature is now very considerable, and probably was 
much greater during the Glacial period, especially if, as appears 
probable, the eastern or Levant basin of the Mediterranean were 
separated from the others; for into this would flow the cold 
waters of the Black Sea and of Central Europe, whilst the Red 
Sea would receive warm water, and be itself exposed to the 
rays of a tropical sun. It would be an interesting subject of 
inquiry—Which of these faunas most closely resembles that of 
the original stock ? 
On the Tay Whale (Megaptera longiman2) and other Whales 
recently obtained in the District, by Prof. Struthers.—Prof. 
Struthers gave a description of the various parts of the anatomy 
of the whale. In addition to the Tay whale members of three 
other whales recently obtained in the district were exhibited 
for the purpose of comparison, and the analogy of its structure 
to that of other animals was specially referred to in order to 
show its identity with the mammal. Prof. Flower joined in the 
discussion which followed, aud remarked that they now had an 
idea at least as to the origin of the whale : it carried its pedigree 
in every part of its body. It had been thought that the mammals 
that live upon land had been derived from progenitors that 
formerly lived in the sea, and that the mammals may have 
passed through an aquatic or marine stage before they took to 
land, but the observations of anatomy showed that this cannot 
haye been the case. There was no doubt that the whale had 
been derived from a four-footed land mammal. All observa- 
tions, for example, had shown that at some period of their life 
whales have a hairy covering, generally in the region of the 
mouth, that hairy covering being functionless and very often 
lost even before birth. In the same way whales at an early 
stage of their existence are furnished with a complete set of 
teeth, the rudiments of the teeth of the land mammal. The 
organ of smell, although in a rudimentary state and in some 
species almost entirely gone, also points to the origin of the 
whale. 
Some Points in the Anatomy of Sowerby's Whale, by Prof. 
Turner.—Prof. Turner remarked that JZesoplodon bidens, or 
Sowerby’s whale, of which he had dissected two specimens, was 
now for the first time dissected so that the viscera of this whale 
were seen by any anatomist, or that its tail and paddle, or fin, 
had been figured. The tail presents a very material difference 
from the customary tail in the cetacea in having the posterior 
border smooth instead of notched. Dr. Turner called attention 
in detail to the intestinal and limb structure of this species of 
whale, showing the affinity or resemblance of the cetacea to the 
reptilious and the amphibious, particularly in reference to the 
corpus. Prof. Flower said he was glad to find that Prof. 
Turner had found some intention for the muscles of the corpus. 
For all that they were very rudimentary as compared with the 
same muscles in other animals, and he thought that he might 
have to modify his views on this point as he had had to do in 
regard to many other things throughout life. Prof. Marsh, of 
Yale College, said the intermediary bone pointed out by Prof. 
Turner interested him much. 
On the Cervical Vertebre of the Greenland Right Whale, by 
Prof. Struthers.—The reduced condition of the upper and lower 
transverse processes was commented on, and the meaning of 
their different parts explained; also the completely fused con- 
dition of the bodies of the seven vertebra. A nearly similar 
condition of the neck of the Pilot Whale (Glodicephalus melas) 
was demonstrated, showing in the young condition the two body 
epiphyses on the rudimentary vertebrae. Other specimens illus- 
trated the fibrous condition of the transverse processes in the 
Narwhal and Beluga. 
On the Development of the Vertebre of the Elephant, by Prof. 
Struthers. —The point was that in the anterior vertebrae the 
neural arches meet behind the body, covering it deeply, and 
shutting it entirely out from forming any part of the wall of the 
spinal canal. 
On the Development of the Foot of the Horse, by Prof. Struthers. 
—Dr. Struthers called attention to the fact that the epiphysis of 
the rudimentary metacarpal and metatarsal bones is not at the 
upper or functional end, but at the reduced end or ‘‘ button,” 
from which only a slender ligament proceeded. This he con- 
sidered a most interesting fact, one which completed the chain 
of evidence of the descent of the horse. There was a reason 
why the epiphyses should be there in the hipparion and previous 
forms from which the horse of the present day was descended. 
The development of the corresponding bones in man, the 
cetacea, and various other mammals, was given in illustration. 
