68 HIALMAR RENDAHL 
All the dorsal and lateral plates densely granulated, the veritral ones less so 
and with a distinct central granule. 
The colour of the specimen, preserved in spirits, is yellowish with irreg- 
ular blackish markings and scattered spots on sides and upper parts. Below 
somewhat translucent. Base of dorsal and anal as well as margin of caudal dark. 
This species is very closely related to O. diaphanus Bl. Schn., from which 
it differs by having the postdorsal bridge formed by three transverse series 
of scutes, a character which it shares with O. fornasini Bianc. This bridge is 
also relatively much shorter than in O. diaphanus, being contained 6 times in 
the total length of carapace, while the same proportion in two specimens of 
O. diaphanus, measured by the writer, with a length of carapace of 152,7 and 
IIl9,5 mm, is 4,8 and 4,9, respectively. Further, the eye is smaller in O. 
diaphanus, its largest diameter in the specimens quoted being contained 9,6 
and 9,4 times in carapace, respectively, while the same proportion in O. pasche 
is 6,9. The diameter of the eye in the measured specimens is as follows: 
O. pasche (carapace 132 mm): 19 mm, O. diaphanus (car. 152,7): 15,7 — (car. 
110;5) 2 12,6: 
15. Diodon holacanthus Lin. 
One specimen, about 125 mm (s. c.), bought in preserved state on Easter 
Island. 
The present specimen agrees entirely with GUNTHER’s description of 
D. maculatus var. a in Cat. Fish. Brit. Mus. VIII (1870) p. 308. 

