1918] Esscnherg: Distrihution of the Pohjnoidae 188 



area, but have been frequently found in depths of 100 fathoms or 

 more. Halosydna insignis has been taken occasionally from a depth 

 of 200 fathoms. A few specimens of Halosydna calif ornica have been 

 taken from depths of 90 fathoms. Harmothoe hirsuta, a typical lit- 

 toral species, has been found occasionally in a depth of 78 fathoms. 

 Harmothoe imhricata is a cosmopolitan littoral species. It is abun- 

 dantly represented on this coast, being usually found between tide 

 marks, but also occurring at various depths, even below 200 fathoms. 

 The examples found beyond 30 fathoms, however, are comparatively 

 few, and the species may be designated as a littoral one. 



2. Deep Water Species 



The converse of what has been said of littoral polynoids is also 

 true of deep sea forms; that is, certain species of Polynoidae are 

 exclusively inhabitants of deep waters and have seldom, if ever, been 

 found in shallow waters. As is indicated in table 3, different deep 

 water species occupy different bathymetric areas. As an example of 

 such deep water species may be given Lepidasthenia gigas. This poly- 

 noid is restricted to a comparatively small area on the coast of south- 

 ern California. It occurs there in great abundance beyond the fifty- 

 fathom line. The greatest depth, however, from which this species has 

 been taken is 140 fathoms. This proves it to be a species of a limited 

 bathymetrical distribution, inhabiting the sublittoral zones. 



Other species again, as Polynoe filamentosa, Antinoe anoculata and 

 Eunoe caeca, have been reported, up to the present time, only from 

 depths of 500 to 1,000 fathoms. Still other species, as Halosydna 

 interrupta, Harmothoe multiseiosa, Harmothoe lamellifera, Lepido- 

 notus caeloris, occur in various depths between 30 and 1,400 fathoms. 

 Those species again have never been found in the littoral zone (1-30 

 fathoms). A number of other species of Polynoidae of this coast 

 appear to be restricted to definite depths and may be justly con- 

 sidered as deep water species (table 5). Moreover, individuals of the 

 same deep water species occupying Avidely separated geographical 

 areas occur in the same relative depths, which serves as further evi- 

 dence that they, under similar conditions of temperature, are deep 

 water species in any part of the world. As an example may be men- 

 tioned Lcpidonotus caelprus, found off Japan between 63 and 155 

 fathoms depth ; while on this coast examples of it have been taken 

 from water varying in depth from 30 to 1,400 fathoms. Another 



