BILATERAL TENDENCIES IN PYCNOPODIA HELIENTHOIDES. 253 



10. Sars, G. O. 



'71 Forhanlinger i Videnselskabet i Kristiania. Side 1-6. 



11. Verrill, Professor A. E. 



'09 Remarkable Development of Starfishes on the Northwest American 

 Coast; Hybridism; Multiplicity of Rays; Teratology; Problems in 

 Evolution; Geographical Distribution. The American Naturalist, 

 Vol. XLIII. 



12. '14 Monograph of the Shallow- Water Starfishes of the North Pacific 



Coast from the Arctic Ocean to California. Harriman Alaska Series, 

 Vol. XIV., Parts I.-II. 



