r also desires to express his thanks to Messrs. Macmillan & Co.
for permission to use figs. 22, 43, 44 and 45, which are taken from
Parker and Haswell's _Text-book of Zoology_; and to Messrs. Swan
Sonnenschein & Co. for the loan of several figures from the
translations published by them of the admirable treatise on
_Embryology_ by Professors Korschelt and Heider; also to the
publishers of the treatise on _Palaeontology_ by Professor Zittel,
Herr Oldenbourg and The Macmillan Co., New York, for several cuts of
extinct forms.

[7] Pocock suggests that the area marked vii. in the outline figure
of the dorsal view of _Limulus_ (fig. 7) may be the tergum of the
suppressed prae-genital somite. Embryological evidence must settle
whether this is so or not.

ARAD, or O-ARAD, a town of Hungary, capital of the county of the same
name, 159 m. S.E. of Budapest by rail. Pop. (1900) 53,903. It is
situated on the right bank of the river Maros, and consists of the inner
town and five suburbs. Arad is a modern-built town, and contains many
handsome private and public buildings, including a cathedral. It is the
seat of a Greek-Orthodox bishop, and possesses a Greek-Orthodox
theological seminary, two training schools for teachers--one Hungarian,
and the other Rumanian--and a conservatoire for music. The town played
an important part in the Hungarian revolution of 1848-49, and possesses
a museum containing relics of this war of independence. One of the
public squares contains a martyrs' monument, erected in memory of the
thirteen Hungarian generals shot here on the 6th of October 1849, by
order of the Austrian general Haynau. It consists of a colossal figure
of Hungary, with four allegorical groups, and medallions of the
executed generals. Arad is an important railway junction, and has become
the largest industrial and commercial centre of south-eastern Hungary.
Its principal industries are: distilling, milling, machinery-making,
leather-working and saw-milling. A large trade is carried on in grain,
flour, alcohol, cattle and wood. Arad was a fortified place, and was
captured by the Turks during the wars of the 17th century, and kept by
them till the end of that century. The new fortress, built in 1763,
although small, was formidable, and played a great role during the
Hungarian struggle for independence in 1849. Bravely defended by the
Austrian general Berger until the 1st of July 1849, i