Contents. v 



PAGE. 



X. Polychcetous Annelids from Florida, Porto Rico, Bermuda, and the Bahamas. 



By AARON L. TREADWELL. 3 plates 255-268 



Family Syllidse 257 



Family Polynolidse 258 



Family Phyllodocidse 262 



Family Leodicidse 263 



Family Sabellidae 266 



Literature 268 



XI. The Microscopic Structure of Striped Muscle of Limulus. By H. E. JORDAN. 



3 plates 273-290 



Material and Methods 276 



Skeletal Muscle 276 



Cardiac Muscle 279 



Literature 282 



Discussion 283 



Summary 287 



Bibliography 289 



Description of Illustrations 290 



XII. Hemopoiesis in the Mongoose Embryo, with Special Reference to the Activity 



of the Endothelium, including that of the Y oik-Sac. By H. E. JORDAN. 



5 plates 291-312 



Material and Methods 294 



Hemopoiesis in Yolk-Sac 294 



Cell-Clusters of the Aorta 298 



Endothelial Hemogenesis in Intraembryonic Mesenchyma 301 



Cell-Clusters of the Pericardium 304 



Discussion 304 



Addendum 305 



Bibliography 311 



Description of Illustrations 312 



XIII. Embryonic History of the Germ-Celh of the Loggerhead Turtle (Caretta caretta). 



By H. E. JORDAN. 6 plates 313-344 



Material and Methods 316 



Descriptive 319 



Literature 327 



Discussion and Conclusions 333 



Summary of Results 340 



Bibliography 342 



Description of Illustrations 344 



XIV. Atresia of the Esophagus in the Embryo of the Loggerhead Turtle (Caretta 



caretta}: A Normal Developmental Condition. By H. E. JORDAN. 4 



plates 345-360 



Material 348 



Descriptive 349 



Discussion 354 



Summary 358 



Literature.. 360 



