1. Agassiz A (1873) The history of Balanoglossus and Tornaria. Mem Am Acad Arts Sci 9:421–436
2. Al C, Colwin LH (1950) The developmental capacities of separated early blastomeres of an enteropneust, Saccoglossus kowalevskii. J Exp Zool 115:263–295
3. Allman GJ (1869) Rhabdopleura normani, Allman, nov. gen. et sp. Report of the British Association for the Advancement of Science 311–312
4. Anderson K (1907) Die Pterobranchier der schwedischen Südpolar-Expedition 1901–1903. Wiss Ergebn Schwedischen Südpolar 5:1–122
5. Angerer LM, Oleksyn DW, Logan CY, McClay DR, Dale L, Angerer RC (2000) A BMP pathway regulates cell fate allocation along the sea urchin animal-vegetal embryonic axis. Development (Cambridge, England) 127:1105–1114