7. ATOPOMYCXEEUS. 315 



cations, each of which is provided with a spine ; the anterior are 

 two-rooted and erectile, the posterior three-rooted and immoveable. 

 Nasal tentacle with two cylindrical and tapering branches ; no 

 nostril. 



Australia ; Cape of Good Hope. 



This genus is very distinct from Chilomycterus, with which it was 

 confounded by Dr. Bleeker. 



1. Dicotylichthys pimctulatus. 



Dicotylichthys pmictulatus, Kaup, Wiegm. Arch. 1855, p. 230. 



Dorsal spines much shorter than those on the sides and abdomen, 

 those in front of the pectorals erectile, those behind three-rooted. 

 Back of the tail without ossifications ; but a root of the last dorsal 

 spine reaches across behind the dorsal fin. There are about 13 

 transverse series of spines between the snout and the dorsal fin. 

 Body with small, round, scattered black spots. A black vertical bar 

 below the eye, a second in front of and a third behind the root of 

 the pectoral fin. 



Australia ; Cape of Good Hope. 



a, h, c. Adult (11 inches), half-grown, and young. Sydney. Pre- 

 sented by G. Krefft, Esq. 



d. Adult : stuffed. Cape. Presented by Sir A. Smith. — Type of 

 the species. 



€. Adult : stuffed. Mauritius ? Presented by Lady F. Cole. 



f-(j. Adult (14 inches) : stuffed. 



7. ATOPOMYCTERUS. 



Diodon, sp., Kaup. 



Atopomycterus, Blcek. Atl. Ichth. Gymnod. p. 49. 



Jaws without median suture. Body covered with dermal ossifi - 

 cations, each of which consists of two roots and an erectile spine. 

 jfasal tentacle as in Dicotylichthys. 



Australia. 



This genus is so closely allied to Dicotylichthys that the propriety 

 of separating it may be questioned. 



1. Atopomycterus nychthemems. 



Diodon nicthemerus, Cuv. I. c. p. 135 ; ? Jemjns, Voy. Beagle, Fish. 

 p. 150 ; Kaup, Wiegm. Arch. 1855, p. 228 ; -Bleck. Verhand, Ak. 

 Wet. Amstei'd. ii. Van Diemeii's Land, p. 25. 



All the spines slender, rounded, without ridge. Upper part of 

 the tail without spines. The roots of the spines are very short and 

 feeble. There are about thirteen transverse series of spines between 

 the snout and dorsal fin. Upper parts blackish brown ; in young 

 individuals the, dark colour descends on the sides in four bands, viz. 



