68 HIALMAR RENDAHL 



All the dorsal and lateral plates densely granulated, the ventral 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 0. 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 0. diaphanus, being contained 6 times in 

 the total length of carapace, while the same proportion in two specimens of 

 0. diaphanus, measured by the writer, with a length of carapace of 152,7 and 

 119,5 mm, is 4,8 and 4,9, respectively. Further, the eye is smaller in 0. 

 diaphanus, its largest diameter in the specimens quoted being contained 9,6 

 and 9,4 times in carapace, respectively, while the same proportion in 0. paschce 

 is 6,9. The diameter of the eye in the measured specimens is as follows: 

 O. paschce (carapace 132 mm): 19 mm, 0. diaphanus (car. 152,7): 15,7 — (car. 

 119,5): 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 GUNTilER's description of 

 D. maculatus var. a in Cat. Fish. Brit. Mus. VIII (1870) p. 308. 



