BIOLOGICAL SURVEY OF WOODS HOLE AND VICINITY. ray) 
Vineyard Sound is not determined by temperature, but by the character of the bottom. 
Nevertheless, after making these allowances, the significance of the facts discussed upon 
the last few pages can scarcely be doubted. 
4. THE AVERAGE YIELD OF THE DREDGE HAULS. 
Another method of portraying synoptically the general facies of our local fauna, as 
revealed by the dredge, is to present the average composition of the dredge hauls. This 
we have computed for the Survey as a whole, and for the separate groups of stations 
which have been distinguished above; for the animal kingdom as a whole, and for its 
main subdivisions. In the following tables certain groups which were represented very 
sparingly in our dredgings, or which were not looked for systematically, and certain 
others which do not properly belong to the benthos have been omitted. 
I. Average number oj genera and species of animals taken per dredge haul. 
Genera. Species. 
Sitvey’ asa whole (4cRStALIOMS) ie 6). cise ete cece ence owe elete ne 34-3 34. 0 
Fish Hawk, Vineyard Sound (218 stations). .................... 33.7 36. 5 
Fust) Hawk, Buzzards Bay'(66 stations)... 2... 2.0.6.2. cane wey GOK 3 38. 7 
dush, Hawi, Cra Ledge. (7\stations) a. by. ois. vee soo) Sea ciedene 37.0 39. 7 
Phalarope and Blue Wing, Vineyard Sound (77 stations)........ Q20r 35.2 
Phalarope; Buzzards Bay (ooistations).5 0... 22.0... 2 eee oe 36.0 38. 5 
While there is a rather surprising uniformity amongst these figures, it will be noted 
that the average number of species is slightly greater for the Fish Hawk than for the 
Phalarope stations; likewise that it is greater for Buzzards Bay than for Vineyard Sound, 
and greatest of all for Crab Ledge. It is of interest, likewise, that the average number 
of genera per dredge haul is nearly equal to that of the species. This point will be 
discussed later. 
II. Average number of genera and species for the 458 regular stations of the Survey, showing 
representation of each group of animals. 
Group. Genera. | Species. Group. Genera. | Species. 
TET) UV UEr OO ANE b SEER ee ATO ETE oh DELETE 7 Cirripedia: \ :iuis aac eee a oe eee : A 
BAIN OZO Wa as 5) Sty syeje. 75,44 s0aipy sf eye go 2% 5 (0 ote.5 2/0 I 4 r.'4) |, Decapoda ..:.\.; «:.). +. n.eeaker eee Pan « 2.8 3-5 
JANTHELTIT ZS se ORE Gio on Ee See | , 4 ASI pRIDOGS «32.020 coieee nee ees 1.6 1.6 
MN GREICTEIH CA ete «Rha 3 Pe hale aeliens sel -04 OF i] | PLSOPOMA .h,, 5,5 i cide 6 leatea cote eee mea oe | al 
LOT EF tg GS PSEC HiTa 8 Oe acm Ge 2.8 2.9 Pyeropanida’ nase st emee eeeet aera. ae 
JST ea) GC Sa ee ee | 8 T..0yi| || Geelecy BOda).6 3. akan eee ae ck: 8.9 9.2 
BONES ERIITEGICLEA Senator. fsck, Sis eyes aici eich Ain ast ‘Am phinerita .\... 7 icaecc cere e aaron -2 .2 
Syed HOTGy ts (AS Ne A Sa 8 .8 Gastropoda. / Siicnteameceee eerie eit oe | 5-9 6.8 
TOIGUHTITOIGCA A a seyaeerarsieteraiciine eden ales | +03 #03\\|| «Cephalopoda ...2)- 5 saci eae ote | .2 -2 
PMEESAILIAEA irr th tis eaten ete cis. erakeke eid snsokeaiess 4-3 4:3 PENT CHES. acu = asl ee EEE PTE EOC -9 I. 
SSIUSTESI CELL AN. ine stas Sait eelttge oo tare ais a6 | .O5 OSE | PRPISCESS v:ssojsc8-d 3,0 0 Sintec ae emer cater ae I. I. 
In the foregoing table, it is nearly certain that the figures for.certain groups, 
especially, perhaps, for the Porifera, do not fairly represent the number of these forms. 
For this reason, indeed, the Foraminifera have been omitted altogether. As stated in 
another section (p. 91), the Foraminifera were looked for systematically during one 
season only, while the Porifera at no time received adequate attention. 
