1921] Schnutt: The Marine Decapod Crustacea of California 287 
distributed as to preclude subdivision into smaller regions or districts 
(ef. appendix I, p. 310). 
Arguing from the distribution of the hydroids of the west coast 
of North America, Dr. C. McLean Fraser asserts (1911, p. 6) that, 
‘“The more the group is studied and the greater the number of loca- 
tions for examination included, the more reason there is for believing 
that there are no sudden, nor comparatively sudden breaks in dis- 
tribution along the entire West Coast, though naturally certain species 
disappear and others as gradually come in.’’ 
In an earlier paper on the same group of organisms (hydroids) 
Dr. Torrey noticed (1902, pp. 6, 7) that ‘‘from Alaska Peninsula to 
San Diego there are no abrupt transitions in the fauna.’’ Although 
thinking ‘‘it possible, for purposes of comparison, to divide this great 
region into four subregions,’’ viz., (1) Alaska Peninsula to Sitka, 
(2) Puget Sound, Vancouver Island and vicinity, (8) San Francisco 
Bay and vicinity, including Monterey Bay, (4) Southern California, 
south of Point Conception, he expressed the feeling, later justified 
by Dr. Fraser, that, ‘‘future exploration will doubtless reduce these 
differences. ’’ 
In a recent monograph on the shallow water starfishes of the north 
Pacific coast from the Arctic Ocean to California, Professor A. E. 
very few are to be found south of the Aleutians in less than 100 fathoms; only 
seven range as far south as Puget Sound, although some ‘‘are often found out of 
their normal region in the cold glacier -fed bays and sounds of southeastern 
Alaska. ’? 
Unalaska is probably the western limit of the faunal region suggested, as 
approximately 20% of the northwardly ranging California and 40% of the ‘‘north 
of California’’ decapods occurring in the Aleutian-Oregon stretch, find there their 
northern limit. 
South of California comparatively little is known of the Lower. Californian 
and Gulf of California faunae other than what has been listed in this paper, or 
in Miss Rathbun’s ‘‘ Descriptions of New Genera and Species of Crabs from the 
West Coast of North America’’ (1893); ‘‘Brachyura of the ‘Albatross’ Voyage, 
1887—1888’’ (1898), and ‘‘Stalk-eyed Crustacea of Peru’’ (1910). An approxi- 
mate tabulation of Miss Rathbun’s lists gives a total of one hundred and twenty- 
four species from the Gulf of California and the west coast of Lower California. 
Irrespective of their southern ranges, forty-three species are not found north of 
the Gulf; thirty are reported from Cape St. Lucas; and twenty-five reach Magda- 
lena Bay; only fifteen go beyond, of which only four are found north of Abreojos 
Point, two at San Bartolomé (or Turtle) Bay, and two off Cerros Island. The 
eleven unaccounted for bear the indefinite locality label ‘‘Lower California.’’ 
Miss Rathbun, in her Peruvian lists, so designated twenty-six species, but refer- 
ence to original sources reduced that number to eleven. 
The papers of Faxon (1895) and Bouvier (1895a and 1898) were consulted, 
but barring species already cited practically none of Faxon’s come within the 
100 fathom limit, while Bouvier described about fifteen new species, all of which 
seem to be confined to the Gulf of California. 
The fauna of the Gulf of California is largely peculiar to it alone, and is 
more related to that of the Panama region than to any further north. 
