134 McMURRICH. [Vol. IV. 



CERIANTHUS AMERICANUS, L. AGASSIZ. 



The earliest mention of this form is by L. Agassiz ('59), who 

 states that it was found by H. James Clark, in 1852, at Charles- 

 ton, S.C., where it lives in tubes sunk in the mud-flats of the 

 harbor. It is referred to the genus CeriantJms, but no specific 

 name is given. Agassiz observed the terminal pore, which he 

 terms the anus, and states that the upper parts of the mesen- 

 teries bear female reproductive organs, and the lower parts 

 male organs. 



The specific name is stated by Verrill ('64) to have been be- 

 stowed in manuscript by Agassiz, and Verrill gives the first full 

 description of the species, from drawings made for Agassiz 

 by his artist, Burkhardt, and from alcoholic specimens in the 

 Museum of Comparative Zoology at Harvard College. 



In a subsequent paper Verrill {'^2) records its occurrence on 

 the coast of North Carolina, where it was collected by Dr. Yar- 

 row, and where it had previously been found by Stimpson, but 

 adds nothing to the description given in 1864. 



Among the "Challenger" material R. Hertwig ('82) found a 

 single specimen of a Cerianthiis obtained in thirteen fathoms in 

 the mouth of the Rio de la Plata. He identifies it with C. Ameri- 

 canos, but unwilling to mutilate the single specimen, did not 

 investigate it anatomically. 



Finally I added {'Sy) a few points to the general description, 

 but gave no account of the internal anatomy and histology which 

 have never hitherto been examined. 



I. External Features. 



The specimens of C. Americanus which I studied were found 

 at Beaufort, N.C., where the Summer Station of the Johns 

 Hopkins University was located in 1885. In the shallow sounds 

 there the bottom is largely very dark mud, sometimes with a 

 superficial coating of sand. Large areas of such mud are 

 uncovered at low tide, forming what are termed the mud-flats, 

 and it is on these flats that Ceriajitfms is found, usually just 

 below the average low-tide mark. It lives in cylindrical burrows 

 extending, usually at an angle, downwards for some distance, 

 how far I was not able to determine. Like other members of 



