AMERICAN MUSEUM NOVITATES 



Number 74 May 9, 1923 



59.51.7(72,2) 



POLYCILETOUS ANNELIDS FROM LOWER CALIFORNIA 

 WITH DESCRIPTIONS OF NEW SPECIES 1 



By Aaron L. Treadwell 



The following taxonomic paper refers to a collection of polychaetous 

 annelids made by the U. S. S. 'Albatross' off the coast of Lower Cali- 

 fornia. The specimens were in most cases poorly preserved, so that 

 determination of species was sometimes uncertain and in a few cases not 

 possible. The families certainly represented and the number of species 

 found in each are shown in the following table. 



Family Old Species New Species 



Amphinomidse 1 



Polynoidae 5 1 



Sigalionidae • 1 



Aphroditidae 2 



Nephth ydidse 1 



Nereidse 3 



Leodicidae 8 



Cirratulidae ? 



Maldanidae 1 1 



Terebellidae 2 



With two exceptions each species is represented by only a very few 

 individuals. These exceptions are Onuphis (Nothria) hiatidentata 

 Moore, and Hyalinoecia tubicola (Miiller) Malmgren subspecies stricta 

 Moore, which together make up more than half the bulk of the collec- 

 tion. In connection with these two species the following ecological note 

 is of interest. 



In his original description Moore comments on the "remarkable 

 example of associative resemblance" which Onuphis (Nothria) hiatiden- 

 tata exhibits, for it lives in close association with Hyalinoecia tubicola 

 Malmgren subspecies stricta Moore and superficially looks more like 

 Hyalinoecia than like Onuphis. I find that it appears to be developing the 

 habit of occupying Hyalinoecia tubes instead of making some of its own. 

 A considerable number were found in what are evidently the normal 

 form of tubes for this species of Onuphis. These tubes are oval in cross- 

 section, have a groundwork of a thin whitish material that looks like wet 

 tissue paper but is extremely tough, and have on the outside more or less 

 foreign matter, the most abundant of which consists of much-worn 



'Scientific Results of the Expedition to the Gulf of California in charge of C. H. Townsend, by 

 the U. S. Fisheries Steamer, 'Albatross,' in 1911; Commander G. H. Burrage, U. S. N., Commanding. 

 X. Published by permission of the U. S. Commissioner of Fisheries. 



