162 Memoirs of the Indian Museum. [VoL. IV, 
G. chiragra has been recorded by Heller (1863, p. 309), and others, from the Medi- 
terranean ; but these records do not seem to be authentic. Steuer (IgII, p. 734) has 
re-examined specimens from Heller’s collection found in the Adriatic, and has shown 
that they are to be referred to Lanchester’s G. chivagra var. mutatus, a form of 
G. glabrous. This is the only record that can be accepted of the occurrence of the genus 
Gonodactylus in the Mediterranean. 
var. platysoma, Wood-Mason. 
1895. Gonodactylus platysoma, \Vood-Mason, Figs. and Desc. of nine Squillidae, p. 11, pl. iii, figs. 3-9 
(sine desc.). 
?1903. Gonodactylus chiragra var. acutus, Tanchester, Faun. and Geog. Maldives and Taccadives, I, 
p- 447, pl. xxiii, figs. 2, 3, 3a. 
? 1910. Gonodactylus chiragra var. acutus, Ienz, in Voeltzkow’s Reise in Ost-Afrika, II, p. 571. 
The specimens to which Wood-Mason gave the name of Gonodactylus platysoma 
seem by their structure to possess better claims to varietal recognition than any of the 
forms listed on p.159. G. platysoma, as its name implies, is much more depressed 
than G. chivagra and is proportionately broader. The greatest breadth of the abdomen 
is from 21°5 to 23°5 % of the total length of the animal including the rostrum, whereas 
it is always less than 20 % in typical G. chivagra. The difference does not appear great 
when expressed in figures, but on actual comparison of specimens is a very conspicuous 
feature (see text-fig., p. 161). 
The measurements of six specimens of var. platysoma are given below in con- 
junction with similar measurements of eight G. chivagra, s.s. With respect to the figures 
of the latter form it is to be noted that in normal specimens the percentage of length to 
Sl =| 
: 2 ® 
a ==} @ 
° oa ga 
: lee ge oS 
LOCALITY. Sex. bos 5 § ga 
23 gs ae 
Ss) ps Oo 
Ss Su Bw 
| 2.4 Se) a 
| a ob) oy 
G. chiragra var. platysoma. mim. mim. % 
Andamans 3 80 17°5 22 
Do. 2 79 185 23°5 
Do. o 77 16°5 21°5 
Society Is. 9g 75 16°0 215 
Mauritius f°) 70 TS 55 21'5 
Do. ; sis 2 48°5 Ir‘o 22°5 
G. chiragra, s.s. | 
Andamans 3 100 1g'0 19 
Do. 3 g2 170 195 
Do. fe) 82 15'0 185 
Do. 9 82 15'5 19 
Do. 3 78 150 19 
Do. Sal 72 130 19°5 
Coco Is we 71 14°0 19'5 
Do. 9 57 po a6) 19'5 
