No. 3.— The Anatomy and Histology of Caudina arenata Gould) 
By Joun Hiram GEROULD. 
CONTENTS. 
PAGE PAGE 
1. Introduction lM cinh rae et petal Pharynx 147 
Methods". ). seuss =) - l20 Stomach 148 
2. Externalfeatures . .. . . 126 Small intestine 148 
3. Habitat, habits, food, etc. . . 128 Large intestine 148 
4. Anatomy and histology of the Cloaca 149 
WOGY-wallly cues cere 2 or enl2d Mesenteries 149 
1. External epithelium . . . 129 . Histology : 149 
2. Connective-tissue layer . . 15 a. Peritoneal epenelaine, 150 
Muscular cylinders . . . 152 b. Outer layer of connective 
3. Caleareous bodies . . . . 153 tissue . 150 
Their development. . . 134 c. Muscle layer . 150: 
Those of C. arenata var. d. Inner layer of connective 
armata. 135 tissue . 152 
4. Musculature 135 e. Inner epithelinan 152 
5. Inner epithelium 54 lBiz/ a. of the pharynx . 152 
SNervOUS System . 95... = «. lev B. of the stomach . 155 
1. Central nervous system . . 138 y. of the small intestine . 153 
a. Circular nerve band 158 8. of the large intestine . 154 
b. Radial nerve bands . .159 7. Respiratory trees 154 
Outerband ; > . . . 140- 8. Calcareousirme. : 155 
Inner band ... . .141 £9. Water-vascular system By ye 
Connective-tissue — parti- 1. Anatomy and histology . . 157 
tion iis Smee sy LAT a. Circular canal 158 
¢. Neural'camals =. . . 141 b. Stone canal and madre- 
Hyponeural canals. . . 141 porite 159 
Epineural canals . . . 142 c. Polian vesicle 160 
Function of neural canals 148 d. Radial canals el Gul 
2. Peripheralnerves . . . . 144 e. Tentacles . 162 
a. Nerves from nerve ring . 144 jf. Posterior branches of UE 
Tentacular nerves . . . 144 radial canal. 164 
Buccopharyngeal nerves. 145 2. Contents of the water-vas- 
b. Nerves from radial bands 146 cular system . 166 
6. Digestive system ... . . 147 3. Circulation of fluids in ire 
1. General morphology .. . 147 tentacles a ohGT 
Mouth... .. . .147 10. System of haemal esas . 168 
1Contributions from the Zodlogical Laboratory of the Museum of Comparative Zodlogy 
at Harvard College, under the direction of E, L. Mark, No. LVI. 
