68 JAMES Francis ABBOTT, 
Explanation of plates. 
Pilates 
Fig. 1. Sketch from life of Coeloplana willeyi, on an Ulva frond. 
10:1. The cylindrical dorsal respiratory tentacles are protruded: the 
armed tentacles retracted within their sheathes. 
Fig. 2. Sketch from life of Coeloplana mitsukuri floating on the 
surface of the water. 2:1. 
Fig. 3. A ciliated rosette viewed from the inner (parenchyma) side. 
900 : 1. m.c¢ muscle cell, ¢. 7 ciliated rosette, c. t “connective tissue cells“. 
Fig. 4. A colloblast or adhesive cell of the tentacles (©. willey:). 
1350:1. n nucleus of cap cell, ¢ mulberrylike arrangement of cytoplasm 
of cap cell, sk skirt of cap cell, sp spiral filament, / central filament, 
o. m outer longitudinal muscle layer of secondary tentacle, g.c¢ giant cell 
floating in interstices between muscle filaments of secondary tentacle, (1 
brushes or converging wedges of transverse muscle fibers, 7. inner layer 
of longitudinal muscles, c. 0 central core of the inner longitudinal muscles. 
Fig. 5. Diagram to show insertion and relation of central and spiral 
filament to cap cell. 
Fig. 6. Sketch from life of otolith region. ca. 20:1. Surrounding 
the otolith is a ring composed of cells that support the otolith. The 
outer yellowish ring is made up of the belt of gland cells of the cup. 
On account of their equatorial position they appear in surface view to be 
external to the band of supporting cells. Surrounding the lips of the 
depression are the branched pigment cells. 
Plate 9: 
Fig. 7. Section through epithelium, parenchyma and tentacle sheath 
of ©. mitsukuriti. 300:1. ep epithelium, composed of a syncytium of 
epithelial cells interspersed with gland cells, the latter in this preparation 
are in the beginning of “Stage C’, s.c¢ flagellate cells lining the tentacle 
sheath, pig. c pigment cell of the parenchyma, m. b group of muscle cells 
in cross section, © group of bodies of uncertain nature, possibly parasitic 
in nature. Interspersed in the parenchyma between the outer epithelium 
and that of the lining of the sheath are numerous isolated muscle cells 
and connective tissue cells. The former form a rather dense layer just 
under the epithelium. 
Fig. 8. Ciliated rosette viewed from the side of the gastric canal, 
out of which it opens. 900:1. ¢p squamous epithelium lining the canal, 
c.r ciliated rosette. 
