XXX 
THE VOYAGE OF H.M.S. CHALLENGER. 
BATHYMETEICAL DISTRIBUTION. 
In regard to bathymetrical distribution, the greatest number of species occur in the 
shallow water (10 fathoms and under), probably because much work was done in this 
region in the pinnace, especially in rich localities, and also because the opportunities for 
collecting between tide-marks were fully taken advantage of ; moreover, the surface-forms 
are included in this division. The two regions ranging from 10 to 50 fathoms and from 
50 to 100 fathoms have each about the same number of Annelids, and both are similar 
in respect to new forms. In the three areas just mentioned, the known species are fairly 
represented, though the majority are new. The number between 100 and 200 fathoms 
is less than the foregoing, but the proportion of new forms is much higher, and several 
are of considerable interest, e.g., Syllis rcanosa. In the rich region ranging from 200 to 
500 fathoms, very few known forms break the long list (the second of the series) of novel 
Annelids. About five new genera are included, and the remarkable types are exemplified 
by Allmaniella, Scalisetosus, Eulepis, Genetyllis ocidata, Macdiiffia, Hemipodus, and 
Euthelepus. The number of species at this depth, however, may be partly due to 
the more frequent dredging therein. Between 500 and 600 fathoms the number 
falls to less than half that in the previous grouj), but the majority are new. The 
number found between 600 and 1000 fathoms include two known S23ecies out of 
a list of fourteen. 
The four sjDecies occurring between 1000 and 1200 fathoms are new. Those between 
1200 and 1500 fathoms are more than five times as numerous as the last, and include 
only five known forms, most of which, however, are found in shallow water as well as at 
this great depth, e.g., Eunice oerstedi, Aricia norvegica, Amphicteis gimneri, and Terehel- 
lides stroemi, the latter three, besides, having a very wide geograj^hical range. About 
the same number were procured between 1500 and 2000 fathoms. All are new, and 
three new genera required to be formed. 
Between 2000 and 2500 fathoms the total numbers about half that just mentioned 
(between 1500 and 2000 fathoms), and all are new, while four new genera are present in 
the series. In the region between 2500 and 3000 fathoms several known forms occur, 
viz., LcBtmonice producta, a marked variety [henthaliana) of which, however, only is 
found at this dej^th, Myriochele lieeri, Amphicteis gunneri (var. atlantica), and Placo- 
stegus 07 'iiatus. If the diagnosis be correct, the latter was first procured by Sowerby in 
shallow water in the Phili^Dpines. The two forms from the profound abyss of 3125 
fathoms are new, though the genera are well known. 
In glancing over the lists, and excluding the pelagic types, it is evident that no 
definite law as to the j^resence or absence of genera at particular depths, can be 
enunciated, though it is true that such genera as Lecena, Eupista, Euthelepus, Melin- 
