EXPLANATION OF PLATE V,

"The Spinning

Illustrating Mr. Cecil Warburton's paper on
Apparatus of Geometric Spiders."

FIG. 1.-Profile of Epeira diademata, sp. spinnerets.
FIG. 2.-Ventral aspect of the same species.

FIG. 3.-Ampullaceal gland.
FIG. 4.-Aggregate gland.

FIG. 5.-Tubuliform gland.
FIG. 6.-Piriform gland.

FIG. 7.-Acinate gland.

FIG. 8.-External spinning organs at rest. a. Anterior, p. Posterior spinnerets. t. Anterior tongue-like fold. 2. Terminal fold of abdomen.

FIGS. 9-13 show the composition of the "trailing-line" under various circumstances. i. Intermediate spinnerets.

FIG. 14.-Stages in the formation of the viscid globules. d. Shows the final arrangement.

FIG. 15.-Teased spiral line, showing that the "ground-line" is double. FIG. 16.-"Attachment disc" (Haftscheibe, Apstein).

FIG. 17.-The same, more in profile.

FIG. 18.-Attachment disc, gluing together irregular strands which held an egg-cocoon in position.

FIG. 19.-Section (somewhat diagrammatic) of aggregate gland at rest. FIG. 20.-Ditto of aggregate gland when the spider had just constructed its web. (The right half only of Figs. 19 and 20 is shaded.)