164 Memoirs of the Indian Museum. [Vor. IV, 
wholly absent, and the submedian ridges in the middle of the dorsal surface are 
strongly convergent posteriorly. 
The only known specimen, a female 56 mm. in length, is recorded by de Man from 
the Mergui Archipelago. Patience has examined an example from the same locality, 
which in the form of the rostrum resembles the type of this species, while the telson 
shows the characters of chivagra (form acutus). 
3: Gonodactylus demani,' Henderson. 
Plate IX, figs. ro8-111. 
1887. Gonodactylus, n. sp., de Man, Arch. f. Naturgesch., LIIT, i, p. 574, pl. xxii a, fig. 7. 
1893.” Gonodactylus Demanii, Henderson, Trans. Linn. Soc. Zool. (2), V, p. 455, pl. x1, figs. 23, 24. 
1905. Gonodactylus Demani, Nobili, Boll. Mus. Torino, XX, no. 506, p. II. 
1905. Gonodactylus spinosus, Lenz, Abhandl. Senck. naturf. Ges. Frankfiirt, XXVII, p. 387, pl. xlvii, 
fig. 12. 
1906. Gonodactylus De Mant, Nobili, Ann. Sci. Nat. Zool. (9), IV, p. 330. 
1906. Gonodactylus de Mani, Nobili, Bull. Sci. France et Belg., XL, p. 158. 
1907. Gonodactylus demani, Borradaile, Trans. Linn. Soc. Zool. (2), XII, pp. 210, 212. 
Igt0. Gonodactylus De Mant, Lenz, in Voeltzkow’s Reise in Ost-Afrika, II, p. 572. 
This species is very closely allied to G. chivagra and appears to be distinguished 
from it only by the following characters :— : 
1. The dorsal processes of the ophthalmic somite are (fig. 108) extremely small and 
inconspicuous and take the form of two very small transverse plates with 
straight or almost straight anterior edges. 
2. The telson (figs. rog—-111) has three swollen ridges in the middle of its dorsal 
surface as in G. chivagra, but the median one is very strongly convex in 
lateral view and its depth, measured from the summit to a point vertically 
below on the inferior surface is equal to half its extreme breadth. The three 
median ridges and those running to the apices of the submedian and inter- 
mediate marginal spines occupy practically the whole surface of the telson 
and are separated from one another merely by narrow V-shaped furrows; the 
interspaces found in G. chivagra are absent. This feature is well shown on 
the submedian spines ; the latter are evenly convex from side to side from 
the apex to the base and never bear a median keel distinct from the general 
surface as in G. chivagra. The telson, in all known specimens except one (var. 
espinosus) is beset with tubercles or spinules that vary greatly in size and 
number. 
In the typical form of G. demani the telson is broader than long, the intermediate 
marginal teeth are well-developed and the lateral teeth, though small, are usually 
quite distinct. The figureson pl. IX (figs. 1rog-111) will give some idea of the range 
of variation in the number and size of the spinules. In most examples they are absent 
' See addendum, p. 198. 
* Henderson’s G. demani has one month’s priority over G spinosus, Bigelow; the latter is here re- 
garded as a variety of the former. 
