1921] Schmitt: The Marine Decapod Crustacea of California 87 
C. nigricauda, but longer and narrower; blade with anterior margin more advanced 
at inner than at outer angle. Fifth segment of abdomen not carinate. 
Dimensions.—Type: from tip of antennal scale to tip of tail 63.5 mm., of 
body from tip of rostrum 52.3 mm. The largest specimen taken in San Francisco 
Bay, an ovigerous female, measured 69 mm. from tip of rostrum to end of telson; 
the general average was between 40 and 45 mm. 
Color—Readily distinguished from all others by the black spot on each side 
of the tail (Lockington). 
Type LocalitySan Diego, California, 6 fathoms. 
Distribution From northern California to Lower California, 3 to 33 fathoms 
(Rathbun). 
Biological Survey of San Francisco Bay—Crago mgromaculata 
is a bottom-dwelling form, rather scatteringly distributed in the mid- 
dle and upper lower bay, and outside within the 30-fathom curve. 
With few exceptions all our specimens were taken on a muddy sand, 
sandy mud, or mud bottom, in 5 to 16 fathoms by means of the sledge 
trawl. Not a single specimen was taken in any of the tow-net hauls. 
In the middle bay out of a return of seventy-eight specimens from 
thirteen stations (18% of the total number) only four hauls of one 
specimen each were not made with the sledge trawl (D 5705, 5-foot 
Tanner trawl; D 5778 and 5779, 19-inch boat dredge and 3-foot Tan- 
ner trawl, and D 5795, oyster dredge), and only three (D 5778, 5779, 
5795 included in the four just mentioned) had a bottom of sand and 
stones or boulders. These three were also the only middle bay records 
not made in the upper and eastern portions of that division. Eighteen 
specimens, all told, were obtained in two seine hauls on the Fort Baker 
Beach. 
In the lower bay fourteen specimens were taken at three stations 
(D 5803-5805; 8% of the total number), all of which were made 
with the sledge trawl off Hunter’s Point, on a soft mud bottom con- 
taining worm tubes in two instances (D 5804, 5805). 
Outside at three stations (D 5736, 5792, 5806, 17% of the total 
number), made with the 9 and 12-foot beam trawls in 9 to 26 fathoms, 
on a fine gray to greenish sand bottom, twenty specimens were 
obtained. 
The ranges of temperature and salinity correlated with the stations 
from which this species is recorded are, respectively, 8.8° to 17.2°C, 
and 27.8 to 34.1. 
The middle bay stations at which Crago nigromaculata was taken 
are: D 5705, 5778, 5779, 5795, 5797, 5799, 5821, 5823-5826, 5828, 5830; 
Fort Baker, April 19 and May 13, 1913. 
