1909] Torrey-Kleeberger: Three Species of Cerianthus. 1-1 



C. benedeni, n. sp. 



This specimen is described from preserved material; color 

 null's are lacking. So far as our information at present extends, 

 it is a resident exclusively of San Diego Bay. There it has been 

 found on the sandy shoals bordering the channel. 



C. benedeni is readily distinguishable from its relative of False 

 Bay by the much larger number of tenacles: 90 to 100 marginals 

 arranged in three cycles; the labials agree in number with the 

 marginals. The body is also larger and its wall much thicker and 

 more muscular. 



In fig. 2, the internal characters of the species are repre- 

 sented senii-diagramnial ically. 



There is a single true siphonoglyph — with a narrow seam-like 

 groove opposite, as in C. aestuari — running the full length of the 

 oesophagus. Compared with the siphonoglyph of C. aestuari, 

 it is relatively narrow, involving fewer mesenteries. 



The mesenteries belong to four orders of differing length, 

 arranged in the "qual roseptes" of Faurot (1895). Approxi- 

 mately eighteen — belonging to the first order — reach the vicinity 

 of the terminal pore, several of the second order reaching almost 

 as far. The directives extend a short distance below the oesopha- 

 gus, but are furnished neither with mesenterial filaments nor 

 gonads. Mesenterial filaments are tightly coiled on the shorter 

 mesenteries — of the third and fourth orders. 



Gonads are confined to the longer mesenteries — of the lirsl 

 and second orders, and are hermaphoditic. as in C. <u si iiari. 



In the foregoing structural characters, C. benedeni resembles 

 C. borealis Verrill closely, differing mainly in the larger number 

 of mesenteries which approach the terminal pore. We come now 

 to the consideration of a difference winch distinguishes C. bene- 

 deni from all other adults, so far as existing descriptions go. 



('. benedt ni possesses no true acontia, of the type found in the 

 Sagartiidae. It is well furnished, however, with the more or less 

 branching, flattened filamentous processes of the mesenterial fila- 

 ments which have been figured in some detail by von Heider 

 (1S79) for G. membranaceus. They occur on all mesenteries 

 except Hie directives. On the mesenteries of the third and fourth 



