34- THE AMERICAN ARBACIA 



internal anatomy and embryology of A. punctulata, having used this 

 book as a laboratory guide for his students at Beaufort, before the 

 Marine Biological Laboratory at Woods Hole was started. An ex- 

 haustive monograph on sea urchins including the Arbaciidae has just 

 been completed by the authority on the subject, Mortensen (1928- 

 1951); A. punctulata is in vol. II, pp. 573-575> i935- 



For a good general description of the njorphology of a sea urchin 

 (Echinus esculentus) reference may be had to MacBride's account in 

 the Cambridge Natural History, vol. i (1906), or to Lankester's Treatise 

 on ^oology, part 3 (1900), or to the more recent volume of Grasse, 

 Traite de ^oologie, t. 1 1 (1948). A more complete comparative account 

 with experimental data and comprehensive bibliography is given in 

 Bronn's Thier-Reich Bd. II, Abt. 3, Buch IV (1904). The excellent 

 volume on Echinodermata in the series of Invertebrateshy Libbie H. Hyman 

 (1955) was published after this book was sent to press. 



