ANATOMY OF ASTRANGIA. 13 
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PLATE II. 
EXTERNAL FORM. 
Fig. 1.—Single animal from the oral side. 
a. Mouth. a’. Peristoma or oral prominence. d. Tentacle. h. Basal region. 5 diameters. 
Fig. 2—The same turned to one side, so that it is seen from the oral and lateral region. The 
tentacles are retracted. 
d. Tentacle. h. Retracted columnar region. g. Region of junction of columnar and basal 
region, basal chambers. 
Fig. 3.—Animal from oral side, with the tentacles partially withdrawn. Mouth (a) assumes a 
sinuous form. 
d. Tentacle. g. Chambers, basal region. 
Fig. 4.—The oral prominence, mouth (a), and tentacles (d). The other soft parts of the body 
are not represented. 
Fig. 5.—The lettering of this figure is not wholly evident. There seems no doubt that the central 
opening (a) is a mouth, through which may be seen unknown structures which may be the tips of 
tentacles. 
g. Chambers of column. h. Centrifugal and centripetal ends of the chambers. 
Figs. 6-10.—Various forms assumed by the mouth or oral slit (a) in different condition of con- 
traction of the lips and peristoma. 
Fig. 11.—Side view of the oral protuberance, or peristome, and tentacles. The mouth is repre- 
sented as open. 
a. Mouth. d, d. Tentacles. 
Fig. 12.—Side view of a retracted animal. The mouth and oral prominence is partially drawn 
into the central region enclosed by the inner wall of the columnar region. The tentacles are so 
retracted that their tips only (d,d) are seen. At h the outer wall of the chambers in the basal region 
is indicated. 
Fig. 13.—View of the base of a single animal. Mouth (a) showing the tentacles (d) at their 
very tips. g. Columnar chambers. h. Chambers of the peripheral region. 
Fig. 14.—Lateral and oral view of the oral region, showing an oral prominence slightly pro- 
truding. 
d. Tentacle. The mouth (a) is at the apex of the peristoma. g. Chambers of the column show- 
ing septa. 
Fig. 15.—Septal and radial mesenterial divisions of the body. 
a. Mouth. g. Basal region, chambers. h. Peripheral region. 
Fig. 16.—The peristoma retracted and mouth open. The tentacles are hidden by the lobes of 
the column, although the tips of two of these organs are seen just above the mouth (a), g, and h, as 
in Fig. 15. 
