Zoology. 75 
EXCRETORY ORGANS OF SpIDERS.—Some recent investigations 
of Dr. J. C. C. Loman ( Tijdsk. Nederl. Dierkunde Vereen i. p. 109. 
1886-7) on the so-called Malpighian tubes of spiders are of 
interest. In sections of a Javanese trap-door spider he finds that 
these organs differ very materially from those of the hexapods and 
agree with those of the amphipods, in the fact that they are diver- 
ticula of the mid rather than of the hind gut. As to the develop- 
ment of these organs in the spiders almost nothing is known, the 
two most recent authors on arachindan embryology—Locy and 
Schimkewitsch—having nothing to offer on the subject. The 
bearing of the observations of Loman tend to show that these 
organs are not homologous in all the “ Trachcates,” and possibly 
that the arachnids and crustaceans are more closely related than is 
admitted in most text-books. 
THe MYLOHYOID GRoovE IN THE Mesozoic AND RECENT 
MAMMALIA.—The Mesozoic Mammalia subdivide into two series, 
nerve and artery branch at this orifice, part entering the canal, 
