48 HARTMAN 



An effort has been made to dissect similar processes from individuals 

 preserved in the tube and partial success has been attained in that there 

 seem to be tentacular structures which are much folded in the buccal 

 region. The small size of mature individuals and the slender proportions 

 of the body make dissection difficult. 



M. gracilis differs from the widely distributed M. heeri Malmgren, 

 which is recorded from colder parts of the northeastern Pacific (Berkeley 

 and Berkeley, 1952, p. 41) in that the prostomium is subcircular, not 

 cylindrical and that the first three setigerous segments are proportion- 

 ately longer and well separated from one another, not short and some- 

 what fused. The uncini differ in their proportions. 



Distribution: M. gracilis comes from San Pedro Basin, California, 

 in 26 to 440 fms with its greatest concentrations in 30 to 54 fms. It 

 is associated with soft bottoms and many other species of annelids ( Hart- 

 man, 1955). 



TEREBELLIDAE 

 Subfamily ARTACAMINAE Chamberlin 



This subfamily has been known for a single genus, Artacama Malm- 

 gren, in which five or six species have been named. It is unique in having 

 a buccal segment that is modified on its ventral side to form a conspicu- 

 ous, proboscis-like organ adorned with papillae, ridges, or other surface 

 structures. 



Artacama is characterized by having 17 thoracic segments provided 

 with pointed setae, first present from the fourth segment ; there are three 

 pairs of branchiae. Uncini appear on the fifth segment and are avicular 

 in shape. 



A species of a different genus has been recovered from quantitative 

 samples in San Pedro Basin, California (Hartman, 1955) ; it differs 

 generically as shown below. 



Artacamella, new genus 

 Tj^pe A. hancocki, new species 



The thorax consists of 15 setigerous segments and the abdomen of 

 many more. Branchiae number three pairs and are inserted on segments 

 one to three ; they are simple, unbranched, and taper distally to slender 



