ANATOMY OF ASTRANGIA. 11 
PLATE TI. 
EXTERNAL FORM. 
Fig. 1—Colonies showing the animal expanded and contracted. Life size. 
4, Club-shaped cluster. g. Coenenchyma between two animals. 7. Animal expanded. g. En- 
crusting colony. 
Fig. 2.—Similar colonies from another cluster. g. Club-shaped colony. 
Fig. 8.—Basal calcareous deposit. Live parts wanting. Colony attached to a Pecten shell. 
Fig. 4.—Colonies in which the individual animals are somewhat isolated and the basal deposit 
ess polygonal than in many specimens of A. Dane. a, 2. Two colonies. 
Fig. 5.—Calcareous radial deposits of the basal region of three contiguous animals. The septa 
are of different lengths (cycles?), extending from the periphery towards the center. a, b, c. Position 
of interseptal mesenteries and chambers. 8 diameters. 
Fig. 6.—Appearance of the calcareous deposits (cycles) when first secreted, arranged in concentric 
rings. 8 diameters. 
Fig. 7.—Several animals, retracted. a, #. Lateral buds. 3 diameters. 
Fig. 8.—Several animals in different attitudes of expansion or contraction. The central animal 
shows the maximum amount of contraction, the soft parts being so withdrawn that mouth and bounding 
wall of the periphery of the animal lie in approximately the same plane. In all the other polypites 
the tentacles are drawn in, but the conical form of the columnar portion of the body is still retained. 
a. Mouth. a’. Peristoma, a conical region of the disk between the mouth and the ring of tentacles 
infolded in the animal, centrally placed and hidden under the soft parts of the columnar region. g. 
Junction of basal and columnar region. h. Basal region. i. Columnar region. 8 diameters. 
Fig. 9.—Single animal isolated from a colony. 
a, Mouth. f. Buds which later form new animals. These last structures are possibly new ten- 
tacles. «@. Structures which arise in a position homologous to that of a tentacle, while @ lies in the 
position which it would naturally have if it were a bud destined to become a new individual. 
Fig. 10.—Lateral view of a single animal with the tentacles beginning to form. 
a. Mouth. d. External peripheral wall. 
Fig. 11.—The same with closed mouth (a). 
Fig. 12.—The same with mouth (a) in the form of an elongated slit. 
Fig. 13—Apex of the oral prominence, with the mesenteric septa showing through the body walls 
a. Mouth. i. Chamber of the column. 
Fig. 14.—The same as last with reniform mouth (a). 
i. Body wall of a radial chamber. 
Fig. 15.—The extended columnar region with half-protruded tentacles (d). 
