ENDEMISM IN THE NORTH PACIFIC 41 



The Studies are based on collections made by the research vessel, 

 Velero IV, of the University of Southern California. A collection of 

 Poeobms rneseres comes from Dr. JMartin W. Johnson, of the Scripps 

 Institution of Oceanography. I am indebted to Mr. Gilbert Grau for 

 the generic name of the deep water pecten. Special acknowledgement is 

 due Captain Allan Hancock, who provided both the Velero IV and the 

 research facilities of the Allan Hancock Foundation. It is a pleasure 

 to dedicate these studies to Captain Hancock, Founder and first Director 

 of the Foundation. 



The endemic nature of polychaetes in the northern and eastern 

 Pacific areas is clearly established through the presence of many species 

 and genera largely or entirely limited to the Pacific. Many such genera 

 are small, monotypic or known for few species. Some are littoral, others 

 abj'ssal, and only a very few are pelagic. In the POLYNOIDAE, the 

 commensal genus Arctonoe Chamberlin is known for three species, all 

 from the northern Pacific; Halosydna Kinberg is represented by twelve 

 of the fifteen known species ; Hololepida Moore by two of the three 

 known species ; the commensal Hesperono'e Chamberlin is known for only 

 two species, both from the northeastern Pacific. 



In the POLYODONTIDAE, Peisidice Johnson is known for a 

 single species from the northern Pacific. In the SIGALIONIDAE, 

 Sthenelanella Moore is limited to California. In the HESIONIDAE, 

 the commensal Hcsionella Hartman, 1939^ is represented by a single 

 species from California. In the PILARGIIDAE, Loandalia Monro is 

 represented by two of the three known species. The PISIONIDAE are 

 known for three genera; two, Pisione Grube and Pisionella Hartman, 

 are known only from the eastern Pacific, the first with two, the second 

 with a single species. 



In the NEREIDAE, Cheilonereis Benham is known for only two 

 species, of which one is northeastern Pacific, the other Australian. In the 

 GLYCERIDAE, Hemipodus Quatrefages is entirely Pacific, with four 

 of the six known species coming from the eastern Pacific. In the ARA- 

 BELLIDAE, the parasitic Labidognathus Caullery is known for only 

 two species, of which one comes from California; Notocirrus Schmarda 

 is known for four species, of which two come from the Pacific. In the 

 SPIONIDAE, Boccardia Carazzi is represented in the Pacific by six of 



'^Hesionella Wesenberg-Lund, 1950, p. 14, erected for H. problematica, oflE 

 southwest Iceland in 555 meters, is a different genus. It is here renamed Wesen- 

 bergia, new genus; its only species is JFesenbergia problematica (Wesenherg- 

 Lund). The genus differs from Hesione Savigny in having two pairs instead of 

 a single pair, of antennae. 



