146 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 19 



Thalassema (communication from the late Dr. W. K. Fisher), the 

 largest measuring 140 mm long, and more than 50 specimens of Chloeia 

 pinnata, together with many other animals. 



Another sample from Redondo Canyon (72) from 40 fms, with 3 

 cu. ft. of mud, yielded 142 living specimens of Dentalium rectius (see 

 list of mollusks by Dr. Norman T. Mattox, below), in addition to 

 hundreds of individuals of other species. Sample 12a, from 229 fms, 

 yielded 323 living individuals of Macoma incongrua, 42 of Nuculana 

 conceptionis, 61 of Tellina carpenteri (according to Dr. Mattox), more 

 than 90 of Chloeia pinnata, and many others (see Analyses, above). 

 Sample 69 contained more than 200 individuals of a sabellid, Chone 

 ecaudate, and 125 of a polynoid, Harmothoe triannulata. 



The largest count that has been made of a metazoan species comes 

 from sample 42b, in 34 fms, 2.14 cu. ft. of mud, where a cirratulid 

 annelid, Tharyx parvus, is represented by more than 1530 individuals. 

 An interesting sample, 63b, from 11 fms, 0.81 cu. ft., of sandy mud, 

 contained hundreds of an anemone, Harenactis, in addition to many 

 other species of animals. Phoxocephalid amphipods have been counted, 

 numbering to 126 individuals in six species from one sample (133) ; 144 

 individuals in six species from another (104) ; and 93 specimens in four 

 species from a third (159a) (see list in Appendix, by Dr. J. Laurens 

 Barnard). 



Based on analyses of the annelids, it is noteworthy that there are few 

 species in the benthos of San Pedro Basin which occur also in intertidal 

 zones of southern California. There are few representatives of nereids, 

 eunicids, serpulids, and some other large families. There are many genera 

 and species which are new records for southern California and also the 

 eastern Pacific (note especially genera and species in Aricidea, Artaca- 

 minae, capitellids, Cossura, flabelligerids, Hauchiella, Leocrates, Mage- 

 lona, maldanids, Myriochele, orbiniids, Paraonis, Petaloproctus, Pholoe, 

 Phyllochaetopterus, Pilargis, Pisione, Saccocirriis, and others). There are 

 relatively few cosmopolitan species. There are many species which appear 

 to have prolonged reproductive seasons, or to lack peaks of high repro- 

 ductivity. 



More than 400 species of metazoan invertebrate animals have been 

 identified from the benthos of San Pedro Basin. The list will be con- 

 siderably enlarged as the various groups of animals are studied. The 

 annelids, with more than 283 species, have been examined by the writer. 

 Twenty-eight species of phoxocephalid amphipods have been identified by 

 Dr. J. Laurens Barnard; 80 species of mollusks have been examined by 



