138 BULLETIN OF THE BUREAU OF FISHERIES. 
Most of the decapods collected by us, being of large size and having rather obvious 
specific distinctions, were listed with full confidence in the field. The others were, for 
the most part, referred to Miss M. J. Rathbun, to whom we are likewise indebted for 
criticizing our check-list of local decapods and for information generously given through- 
out the progress of this work. To Dr. R. P. Bigelow we are indebted for the identifica- 
tion of a number of specimens collected during the first season of the dredging work. 
Errors due to the confusion of one species with another in our dredging records are 
probably negligible in extent, excepting, perhaps, such as may relate to the small crabs 
of Panopeus group (now split into several genera). Upon this point the reader is 
referred to the statements made under the head of Eurypanopeus depressus, Neopanope 
texana sayi, and Hexapanopeus angustijrons in the annotated list. It seems possible 
that specimens identified by the collectors as “Panopeus sayi’’ were in some cases 
referable to one of the other species. It is probable, however, that the great majority 
of these crabs actually belong to the species last named, since none of the others are 
comparable with it in respect to frequency of occurrence. The examination of a 
large number of our specimens by Miss Rathbun indicates that Eurypanopeus depressus 
is at present comparatively rare in these waters, being by no means the common species 
which one would infer it to be from the statements of Smith. 
The average number of species of decapods recorded by us from the 458 regular 
stations of the Survey is 3.5 per dredge haul. By far the most prevalent single species 
was Pagurus longicarpus, which was recorded from 290, or over 60 per cent, of the 
stations. Those species which were dredged at one-fourth or more of the total number 
of stations (arranged in order of frequency) are: 
Number of stations. 
4 Sfr tag Fg BIS pS Foe 1 2 (e420 oI RIOT YA eS ee a Ra aR Hie el el aN Foc 290 
Ca CER IGhOLAUSh ee en 2 o ey ep Secs ois nies, scala Safe meen ech mee emeene 209 
Pactitts aimnitlipess iis. eo SR leer eeeten es clk So. 3 wpe suena Th OR. 196 
LibiniaGimareinata sss fs 14 wqletae. aris airtel eee ol wl. ae eee 2 he Barge ee 192 
Crago Septemispinosus: :..5% -biimiataee + ptet DPR eRe ae MIA e 169 
Neopanope bexana saya. cas cctye asta pie's+ ciao. ous)ehcye auth Re A 143 
For the various groups of dredging stations and for the various types of bottom 
the averages are surprisingly uniform. The following figures are taken from the tables 
on pages 78 and 79: 
Vineyard Sound: 
Fish Hawking tecenc® ohh Sper oievole sree eso De ysls Sutera es ep res eeeasl el aie aS ope ate 3.8 
Bhalaro pes 79 ga ee Patera ey sise oie ere cir REET Ctr os bia Sen ty BZ 
Buzzards Bay: 
Bhsha awk 5 A Pa ES OS I I OI AES tS 3.4 
Phalarope: . .... 2 ARR tities ho Sey at i ee ine Nr 5 syetd Bee 
Type of bottom: 
SAAN GL isis cos Sepsis sa bale ad ER RENT ELE oe CIENCIA ce A EV oR Bia 305 
Stones and! gravel! es enemy yee eee aca tacts siete pee ea epee RE tet aa ot 3.5 
1, 6 RO aR es SOP EE a in ea iia eS PR Pt il ong ad EA Bo 3.6 
The lists of ‘‘prevalent’’ species for these different groups of stations are likewise 
surprisingly uniform in respect to the species comprised. Of the 6 species listed for 
one-fourth or more of the total number of stations, 3 appear in all seven of the lists 
of ‘‘prevalent”’ species; 2 others appear in all but one of these lists, while the remaining 
species appears in five of the seven lists. The lists of “prevalent” species for the three 
types of bottom comprise 5 species each. Of these, 4 are common to all three lists. 
