No. 2.— The Anatomy and Histology of Caudina arenata Gould. 1 
By John Hiram Gerould. 
CONTENTS. 
Page 
Page 
1. Introduction . 
8 
Pharynx. 
31 
Methods. 
9 
Stomach. 
32 
2. External features. 
10 
Small intestine .... 
32 
3. Habitat, habits, food, etc. . . 
12 
Large intestine .... 
32 
4. Anatomy and histology of the 
Cloaca . 
33 
body-wall. 
13 
Mesenteries. 
33 
1. External epithelium . . . 
13 
2. Histology. 
33 
2. Connective-tissue layer . . 
15 
a. Peritoneal epithelium . . 
34 
Muscular cylinders . . . 
16 
b. Outer layer of connective 
3. Calcareous bodies .... 
17 
tissue. 
34 
Their development . . . 
18 
c. Muscle layer. 
34 
Those of C. arenata var. 
d. Inner layer of connective 
armata. 
19 
tissue. 
36 
4. Musculature. 
19 
e. Inner epithelium . . . 
36 
5. Inner epithelium .... 
21 
a. of the pharynx . . . 
36 
5. Nervous system. 
21 
(3. of the stomach . . . 
37 
1. Central nervous system . . 
22 
■y. of the small intestine . 
37 
a. Circular nerve band . . 
22 
8. of the large intestine . 
38 
b. Radial nerve bands . . 
23 
7. Respiratory trees. 
38 
Outer band. 
24 
8. Calcareous ring. 
39 
Inner band. 
25 
9. Water-vascular system . . . 
41 
Connective-tissue parti- 
1. Anatomy and histology . . 
41 
tion . 
25 
a. Circular canal .... 
42 
c. Neural canals .... 
25 
b. Stone canal and madre- 
Hyponeural canals. . . 
25 
porite. 
43 
Epineural canals . . . 
26 
c. Polian vesicle .... 
44 
Function of neural canals 
27 
d. Radial canals .... 
45 
2. Peripheral nerves .... 
28 
e. Tentacles . 
46 
a. Nerves from nerve ring . 
28 
/. Posterior branches of the 
Tentacular nerves . . . 
28 
radial canal. 
48 
Buccopharyngeal nerves. 
29 
2. Contents of the water-vas- 
b. Nerves from radial bands 
30 
cular system. 
50 
6. Digestive system. 
31 
3. Circulation of fluids in the 
1. General morphology . . . 
31 
tentacles. 
51 
Mouth. 
31 
10. System of haemal lacunae 
52 
1 Contributions from the Zoological Laboratory of the Museum of Comparative Zoology 
at Harvard College, under the direction of E. L. Mark, No. 5G. 
