22 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 39. 



larger than the lateral ones; the neiiropodia of the first few seg- 

 ments are very small, in fact, it is often impossible to see them 

 on the first three segments and that of the fourth segment is a very 

 short sht, the neiiropodia of the posterior branchial region are long 

 dorso-ventrally, they and their grooves reach almost to the mid- 

 ventral line; six pairs of nephridia which open on the fifth to the 

 tenth segments; one pair of oesophageal glands, conical, cylindrical, 

 or clavate and comparatively short; a pair of well-developed, muscular 

 finger-shaped pouches projecting backward from the first septum; a 

 pair of statocysts, closed, spherical or ovoid sacs, each containing a 

 single, large, secreted, statolith. 



This species has been recorded from the following stations on the 

 American coast: 



A. cristata, Woods Hole, Massachusetts. C. M. Child, Arch. Entwickelungsmech, 

 vol. 9, 1900, p. 587. 



A. cristata, Woods Hole, Massachusetts. R. S. Lillie, Mitth. Zool. Stat. Neapel, 

 vol. 17, 1905, p. 344. 



A. cristata, North Falmouth, Massachusetts. C. M. Child, Arch. Entwickelungsmech, 

 vol. 9, 1900, p. 587. 



A. cristata. New Jersey. H. E. Webster, 32d Ann. Rept. New York State Mu- 

 seum, p. 117, Albany, 1879. 



A. cristata, Anglesea, New Jersey. J. E. Ives, Proc. Acad. Nat. Sci. Phila. for 

 1890, p. 73, Philadelphia, 1891. 



A. cristata, Beaufort, North Carolina. E. A. Andrews, Proc. U. S. Nat. Mus., 

 vol 14, p. 289, Washington, 1892. 



A. cristata, Charleston Harbor, South Carolina. W. Stimpson, Proc. Boston Soc. 

 Nat. Hist., vol. 5, 1856, p. 114. 



A. antillensis, Florida, Captiva Key, Florida. E. Ehlers, Mem. Mus. Comp. 

 Zool. Harvard, vol. 15, 1887, p. 173. 



A. cristata, Captiva Key, Florida. F. W. Gamble and J. H. Ashworth, Quart. 

 Journ. Micr. Sci., vol. 43, 1900, p. 423. 



A. cristata, Manatee River, Florida. J. E. Ives, Proc. Acad. Nat. Sci., Phila. for 

 1890, p. 74, Philadelphia, 1891. 



A. cristata, Bermuda. H. E. Webster, Bull. U. S. Nat. Mus., No. 25, p. 523, 

 Washington, 1884. 



A. cristata Bermuda. A. E. Verrill, Trans. Conn. Acad. Arts and Sci., vol. 10, 

 pt. 2, 1900, p. 599; vol. 11, 1902, p. 39; vol. 12, 1907, p. 147. 



A. cristata, Bluefields, Jamaica. F. W. Gamble and J. H. Ashworth, Quart. 

 Journ. Micr. Sci., vol. 43, 1900, p. 423. 



A. antillensis, St. Croix (Santa Cruz). C. Lutken, Vid. Medd. Naturh. For. 

 Kjobenhavn, Aaret 1864, 1865, p. 121. 



This is one of the most readily recognized species of Arenicola 

 by reason of its seventeen chaetigerous segments, eleven pairs of large 

 gills, and the beautifidly pinnate character of the gills which is so 

 marked a feature of most of the specimens. The character of the 

 gills of Liitken's specimens was so striking that he held it to be a 

 sufficient basis for the deHmitation of a new subgenus for which he 

 proposed the name Pteroscolex. 



