ARACHNIDA. 265 



its fellow through the medium of a third shorter middle canal, forming 

 three meshes on each side, and a seventh longer anterior loop by the 

 terminal union of the oviducts before they open upon the bivalvular 

 vulva. 



The ovaria consist of lateral appendages going off at right angles 

 from the longitudinal canals_, and expanding into elliptical sacculi 

 before communicating with the canals : the ova are developed in the 

 slender blind free extremities or beginnings of the ovaria, and the 

 embryo is developed in the sacculus, the scorpion being viviparous. 

 The course of its development, which would be a subject of great in- 

 terest, has not yet been traced. 



Spiders are oviparous. The mother prepares a soft and warm 

 nest for the eggs, which she guards with great care. The Lycosa 

 vagahunda carries her cocoon about with her : if it be removed and 

 a ball of cotton substituted, she has been known to bestow upon it 

 the same care ; but when the cocoon was offered together with the 

 cotton ball, she seldom failed to select her own fabrication. The 

 Saltica selects an empty snail-shell for her cocoon, and spins a silken 

 operculum across the mouth. The Epeira fasciata incloses her eggs, 

 which are as big as millet-seed, in a papyraceous cell, surrounded by 

 a cottony covering, which she then suspends by a dozen threads or 

 pillars to a larger chamber of silk. The whole is attached to a branch 

 of a high tree, and is guarded by the mother, who quits it only in 

 extreme danger, and returns when this is past. 



The ovum of the spider, at its exclusion^ consists of a large and 

 finely granular vitellus, invested by the membrana vitelli, which is 

 separated from the chorion by a very thin structure of colourless 

 liquid, analogous to the albumen or the white of the hen's e^g. The 

 yolk is generally of a yellow colour ; but in some species of spider is 

 grey, white, or yellowish brow^n. An opake white elliptical spot in- 

 dicates, at this period, the metamorphosed and impregnated centre 

 from which subsequent development radiates. The previous changes 

 which have led to this condition of the excluded ovum have not 

 hitherto been studied : the subsequent ones, up to the complete for- 

 mation of the young spider, have been described and figured by the 

 accurate and industrious Herold. 



The germ-spot consists of minute opake whitish granules, of smaller 

 diameter than those of the vitellus : in some species Herold observed 

 several germ spots on different parts of the superficies of the yolk, 

 which rapidly coalesced into one body. Development commences by 

 expansion of the circumference of the germ-spot, which, as it expands, 

 covers the yolk with a semitransparent thin layer, the basis of the 

 future integument. Herold next describes the granules of the germ 



