Published in Proc. Acad. nat. Sci. Philad., in 1911, in volume 63, pages 440-456

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1911, in volume 63, pages 374

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1911, in volume 63, pages 336-373

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1911, in volume 63, pages 319-335

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1911, in volume 63, pages 548-549

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1911, in volume 63, pages 174-199

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1911, in volume 63, pages 523-524

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1911, in volume 63, pages 521-522

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1911, in volume 63, pages 487-492

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1911, in volume 63, pages 234-318

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1911, in volume 63, pages 438-439

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1911, in volume 63, pages 457-468

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1911, in volume 63, pages 1

Published in Proceedings of The Academy of Natural Sciences of Philadelphia, in 1911, in volume 63, pages 605