NO. 1 HARTMAN, BARNARD: BENTHIC FAUNA OF DEEP BASINS 13 



and many small metazoan animals of diversified kinds. The subsill waters 

 over the sediments support a unique hydrozoan medusa (Hartman and 

 Emery, 1956) not found in similar abundance in any other area of 

 southern California. Adjacent areas of the basin, as shown by a sample 

 58 meters above sill depth, have been found to contain as many as 291 

 individuals in 48 species, with a biomass value of 76 grams per square 

 meter. 



The floor of Santa Cruz Basin has been sampled only along its 

 southwest wall and into its deepest part. It is the only one from which 

 simple ascidians have been recovered (Appendix V). 



San Nicolas Basin is partly known from two photographs and a 

 benthic sample. One photo at 1778 meters (Plate 2, fig. 1) shows an 

 abundance of surface life with sea-whips and urchins, perhaps Allocen- 

 trotus fragilis; the other at 1738 meters (Plate 2, fig. 2) shows at least 

 two comatulid crinoids, perhaps Florometra, not in sharp focus. The 

 benthic sample from sta. 5116 was nearly barren except for the shells 

 of foraminiferans. If the metazoan animals are widely dispersed, as seems 

 likely, it may be necessary to take many samples to determine biomass 

 and bio-index values. The basin would appear to have a diversified bottom 

 fauna. 



Tanner Basin is known from a photograph (Plate 1, fig. 2) and a 

 bottom sample. The photo shows two comatulid crinoids and surface 

 irregularities which are perhaps the burrows and mounds of metazoan 

 animals, such as tubicolous annelids (onuphids and maldanids), burrow- 

 ing brissopsid urchins, holothurians, and others. The single sample from 

 sta. 5120 yielded two large individuals of an onuphid, Nothria iridescens 

 (Johnson), in addition to a few smaller animals (Appendix IV). The 

 finer screenings contained subspherical foraminiferans and radiolarian 

 tests. 



West Cortes Basin is known from a single sample containing another 

 kind of large onuphid, Onuphis vexillaria Moore, which was not taken 

 in the other basins. The sediment contained tests of foraminiferans. 



San Clemente Basin, known from a single sample, supports a large 

 abyssal foraminiferan Cyclamina cancellata Brady, not recovered from 

 other basins. 



Judging from these results, the outer basins have faunas distinct from 

 those of the nearshore basins. The Santa Catalina, Santa Cruz and San 

 Nicolas Basins support a deep water fauna consisting of several echino- 

 derms (a crinoid, several ophiuroids, one or two echinoids and a holo- 

 thurian), annelids of several kinds, a sipunculid, sea-whips and a few 



