GLYPHOCRANGON NOBILIS. 1438 
dorsal keel, most pronounced near the anterior end, runs backward, becom- 
ing obsolete abreast of the posterior pair of lateral spines. In nearly all of 
the specimens the dorsal side of the rostrum is roughened in the middle por- 
tion of its length by transverse corrugations on each side of the median 
carina. The lower face of the rostrum is distinctly margined; the margins 
gradually converging at each end, leaving between them a lanceolate field 
which is divided anteriorly by a light median carina. This median ventral 
carina of the rostrum is characteristic. I have found it wanting in but one 
or two out of the twenty-three specimens examined. The general trend of 
the rostrum is lightly downward to a point near the tip, then upward to 
the tip. 
The two or three tubercles that represent the anterior part of the second 
lateral carina of the carapace are produced to spinous points, the foremost 
forming a pair of prominent spines at the front part of the gastric region. 
The prominent carina (fourth) which runs along the hepatic area is produced 
at its anterior end into a distinct, acute, though not large spine, which is 
divided from the rest of the carina posteriorly by a notch or sinus. All the 
carine except the two uppermost have a worn and eroded surface. The an- 
terior part of the third crest is represented by a single tubercle on the hepa- 
tic area. The lower margin of the second abdominal pleura is often one- 
toothed, the anterior and posterior angles being rounded off and destitute of 
spines. The tubercles of the abdomen are more sparse and less pronounced 
than in the type of G@. nobilis, as inferred from Milne Edwards's figures. The 
telson, like the rostrum, varies in length in different specimens. In those with 
the longest rostrum the telson is one-third longer than the swimmerets, while 
in others it is not over one fifth longer than these appendages. It is up- 
turned at the tip, very lightly in the majority of specimens, but very 
strongly so in the specimens with the longest telson. There is a later- 
ally compressed tooth in the median dorsal line at the base of the telson 
which forms the posterior end of the median carina of the abdomen. The 
dorsal pair of longitudinal carinz are obsoletely spinose on their anterior 
third. 
In the type specimen of G. longirostris Smith, the rostrum is widened mid- 
way between the anterior pair of lateral spines and the tip, thus assuming 
a lanceolate outline; the corrugation of the dorsal surface of the rostrum 
specimens, and the median dorsal 
oJ 
is more emphatic than in the “ Albatross’ 
carina is continued backward to the gastric area; the tubercles on the an- 
