> CL OS REPRODUCTIVE AND NERVOUS SYSTEMS 333 
in the cephalothorax, one median and the others lateral, con- 
siderably dilated in front, in the region of the eyes, and connected 
by transverse passages. By these the blood is brought back 
through the pedicle to the lung-books. In the abdomen also 
there are three main sinuses, two parallel to one another near the 
lower surface, and one peneath the pericardium. These likewise 
bring the blood to the lung-books, whence it is conducted finally 
by pulmonary veins (Fig. 186) back to the pericardial chamber, 
and thus, by the ostia, to the heart. 
The Spider’s blood is colourless, and the majority of the 
corpuscles are “amoeboid,” or capable of changing their shape. 
Generative System.— The internal generative organs present 
no great complexity, consisting, in the male, of a pair of testes 
lying beneath the liver, and connected by convoluted tubes, the 
“vasa deferentia,” with a simple aperture under the abdomen, 
between the anterior stigmata. 
The ovaries are hollow saes with short oviducts which presently 
dilate to form chambers called “ spermathecae,” which open to the 
exterior by distinct ducts, thus forming a double orifice, fortified 
by an external structure already alluded to as the “epigyne.” 
The eggs project from the outer surface of the ovary like beads, 
connected with the gland by narrow stalks, and it was not at 
first clear how they found their way into the interior cavity, but 
it has been ascertained that, when ripe, they pass through these 
stalks, the empty capsules never presenting any external rupture. 
The palpal organs have already been described. The sperma- 
tozoa, when received by them, are not perfectly elaborated, but 
are contained in little globular packets known as “ spermato- 
phores.” 
Nervous System.—The Spider’s central nervous system 1s 
entirely concentrated in the cephalothorax, near its floor, and 
presents the appearance of a single mass, penetrated by the 
oesophagus. It may, however, be divided into a pre-oesophageal 
portion or brain, and a post-oesophageal or thoracic portion. 
The brain supplies nerves to the eyes and chelicerae, while 
from the thoracic mass nerves proceed to the other appendages, 
and throngh the pedicle to the abdomen. The walls of the 
oesophagus are closely invested on all sides by the nerve-sheath 
or neurilemma. 
Sense Organs.—Spiders possess the senses of sight, smell, and 
