Gerould. — Caudina. 
PLATE 3. 
Abbreviations. 
aq. r. 
Radial water canal. 
mu. r. hue. 
Radial muscles of buccal 
e'n. crc. 
Circular epineural canal. 
region. 
e'n. r. 
Radial epineural canal. 
n. r. ex. 
External band of radial 
en'th. 
Endothelium. 
nerve. 
fbr. sst. 
Supporting fibers _ of 
n. r. i. 
Internal band of radial 
nerve bands. 
nerve. 
k’pn. r. 
Radial hyponeural canal. 
n. ta. 
Nerve to tentacle. 
mu. crc. 
Circular muscle fibers. 
sep. 
Connective-tissue parti¬ 
mu. Ig. 
Longitudinal muscles of 
tion. 
body-wall. 
sng. r. 
Radial blood sinus. 
mu. Ig. ta. Longitudinal muscles of 
sul. 
Furrow upon the surface 
tentacles. of the nerve ring. 
Fig. 17. Seven large and four smaller calcareous bodies drawn in their natural 
position in the integument; seen from without. X 280. 
Fig. 18. Calcareous table; side view. X 280. 
Fig. 19. Calcareous table ; oblique view. X 280. 
Fig. 20. Spicule from the superficial layer of the calcareous ring. X 280. 
Figs. 21-24. Calcareous rods from the deeper portion of a radial calcareous 
plate. X 280. 
Fig. 25. Spicules from the madreporic body. X 270. 
Figs. 26-33. Series illustrating the development of the calcareous tables. 
X 280. 
Fig. 26^. Same as Fig. 26, but enlarged and showing cells adjacent to it. 
X 460. 
Fig. 33. Calcareous table, showing the method of development of the leg. 
Figs. 34-36. Calcareous bodies from the integument of C. arenata armata 
Viewed from their outer surfaces. X 280. 
Fig. 37. The same ; side view. 
Fig. 38. Longitudinal section through the posterior part of the nerve ring. 
(Comp. PL 4 , Fig. 44.) 
Fig. 39. Longitudinal section of the nerve ring, showing its anterior furrow 
and the tendency of ganglion cells to be arranged in lines. X 490. 
Fig. 40. Cross section through the radial nerve and accompanying organs. 
X 280. 
Fig. 41. Transverse supporting fibers from a cross section of the nerve ring. 
X 460. 
Fig. 42. Cross section of the nerve ring. X 360. 
