210 PERCY SLADEN TRUST EXPEDITION. 
with minute spines, at each side a keel bearing a row of blunt teeth, and above four low 
mounds, two in the middle line and two at the sides, each bearing a few sharp knobs. 
Length 18 mm. 
One male specimen dredged at Providence, D1, 39 fathoms. 
Genus GONODACTYLUS, Latr., 1825. 
The taxonomy of this genus is at present in some confusion. In the following keys I 
have endeavoured to arrange the species and varieties in order. 
Key to the Species of Gonodactylus. 
I, First joint of exopodite of uropod has the teeth of the outer edge curved 
forwards, and bears a long second joint at some distance from the end. 
Angles of rostrum form sharp teeth. [Telson bears a large middle 
swelling, with on each side a smaller ridge and outside this again a still 
slighter ridge, and has the intermediate teeth of the edge well developed. ] 
1. Endopodite of uropod curved outwards. Telson smooth, but 3 knobs at 
end of middle swelling. Outer teeth of telson-edge wanting. G. fimbriatus, Lenz, 1905. 
2. Endopodite of uropod curved inwards. Telson bears numerous stout thorns. 
Outer teeth of telson-edge well developed. . . . . . . G. drepanophorus, de Man, 1902. 
3. Related here, but with most of the uropod-teeth straight,is . G. herdmani, Tattersall, 1906. 
Il. First joint of exopodite of uropod has the teeth of the outer edge curved 
backwards or nearly straight, and bears a short, broad second joint near 
the end. Angles of rostrum do not form sharp teeth, except in 
G. acutirostris. 
1. Three long keels on the telson (not including those of the edges), with or 
without a short keel on each side of the hinder end of the middle keel. 
i. Intermediate teeth of the telson-edge well developed. 
(1) Angles of the rostrum form sharp teeth. Keels of submedian teeth 
of telson-edge converge forwards. ‘The small knob usually found in 
the genus on each side of the telson near its fore edge is wanting. 
G. acutirostris, de Man, 1898, 
(2) Angles of the rostrum blunt. Keels of submedian teeth of telson- 
edge do not converge forwards. The above-mentioned knob is in 
most cases well developed, and at least faintly indicated. 
(i) No ridge on the inner side of the keel of the intermediate tooth of 
the telson-edge. Indo-Pacific. 
a. Telson and endopodite of uropods bear long spines . G. acanthurus, Tattersall, 1906. 
6. Telson smooth, though there may be spines at the end of the 
keels. No spines on endopodite of uropods . . . G. chiragra (Fabr.), 1793. 
c. Telson bears scattered thorns. Uropodsas G. chiragra. G. demani, Hend., 1894. 
(ii) A ridge on the inner side of the keel of the intermediate tooth 
of the telson-edge. W. Atlantic. 
Goplelson smoothes aries wee wo sl Ue) 6s 6G. rstedseBlansen  s9p: 
b. Telson roughened with smal) ae MSM se Ss |G. festemINODIM EL OUee 
. Intermediate teeth of the telson-edge obsolete. 
(1) Telson smooth". “1a; eee to soa) lal G.xespenosussbornaplouas 
(2) Telson roughened with small dich Pit Riedie! 6 a) Gi epinosus Bigelow, woo: 
