964 DR. H. J. HANSEN ON CRUSTACEANS [Dee. 1, 
To his description it may be added that each of the four anterior 
abdominal segments possesses in the median line on the inferior 
side a protuberance or lobe, the three anterior of these ending in 
a spine; on the ext. br. of urp. the exterior margin is ciliated in 
$ of its length, thus a very short basal part being naked, but no 
tooth or spine is present. 
S. vigilax, Stimps.—The description of Stimpson (p. 45) agrees 
rather well with the oldest Mastigopus, and no other species 
known to me agrees with it; his animals were captured at the 
Azores. Specimens c. 9-16 mm. in length are distinguished from 
the related forms by the following characters :—The rostrum about 
as in S. oculatus, Kr., but perhaps a little larger, directed upwards 
and forwards; in specimens 9-10 mm. in length the apex is 
produced into a short spine directed forwards. The eye-stalks are 
very long, obviously longer than in S. oculatus, Kr.; the eyes large. 
In the antenn. ped. the first and third joints are of about equal 
length. The abdominal segments are dorsally smooth, yet in speci- 
mens 9-10 mm. long with very short spines or traces of spines on 
the fourth, fifth, and sixth segments. On the ext. br. of urp. the 
ciliated part occupies from 3? (in the younger specimens) to more 
than 4 (in the older specimens) of the exterior margin, but the 
spine is generally obsolete. The adult form is described above, 
bearing the same name.—As already pointed out by Ortmann, 
S. parvidens, Bate (p. 409, pl. lxxiv. fig. 3), 9 mm. long, is estab- 
lished on younger specimens of S. vigzlax, with dorsal spines on 
the fourth to sixth abdominal segments. Bate’s figure gives a 
rather good idea of this stage. S. macrophthalmus, Stimps. (p. 46), 
is, in all probability, identical with the stage parvidens, Bate. 
The smallest specimen seen by me (captured by Chun at the 
Canaries) is (the rostrum included) 4 mm. long, and differs con- 
siderably in several particulars from the older specimens, but is 
more similar to S. brachyorrhos, Kr. The rostrum is about ? as 
long as the eye-stalks, its short basal part broad, and at its end a 
dorsal spine, beyond which the rostrum is very slender. The 
supraocular and the hepatic spinesare considerably elongated. The 
antenn. ped. extremely slender, only 2-jointed, as the second joint 
is not yet separated from the first; the third is not ; of the entire 
peduncle. The posterior margin of the carapace in the median 
line with a slender spine directed obliquely forwards (this spine 
is still preserved in specimens ce. 8 mm. long, but then shorter and 
almost perpendicular). Each of the 6 abdominal segments with a 
dorsal spine, which is short and perpendicular on the first two 
segments, longer on the third, fifth, and sixth, very long on the 
fourth segment. The epimera of the 5 anterior segments produced 
into a short spine directed outwards; the same segments besides 
inferiorly in the median line with a lobe, which at least on the 
second segment is armed with a spine. The very narrow ext. br. 
of urp. with the exterior margin ciliated in scarcely more than 3 
of its length, and the spine is well developed. The telson very 
short as in S. brachyorrhos, Kr. 
