A CONTRIBUTION TO THE ICHTHYOLOGY 183 



margin. In the dorsal middle line, they anteriorly extend to a 

 line drawn between the posterior third of the eyes, there are 

 12 scales before the first dorsal spine. Praedorsal space 44,9% 

 of the body-length (s. c). Opercles scaly, below the eye there 

 are two longitudinal rows of scales on the praeopercle. Latter 

 measured from its angle to border of eye 3,6 in length of head. 



Dorsal fins with V and I. 13 rays, the first dorsal origina- 

 ting above the 8th., the second above the 15th. transverse row 

 of body-scales. Anal with I. 20 rays, originating below the middle 

 of the first dorsal and the 7th row of body-scales. Pectoral 

 with I. 13 rays, slightly more than % length of head, its base 

 equally distant from the dorsal and ventral middle lines. Prae- 

 ventral space (measured from tip of snout to base of ventral fin) 

 37,9%, praeanal space 49,4% of body-length. 



There are in a longitudinal row 34 scales, in a transverse 

 12. The height of the caudal peduncle is 11,1% of the length 

 of the body. 



The ground-color of the fish is (in spirits) a light brown. 

 Along the sides of the body, occupying the adjacent two-thirds 

 of the scales, there is a broad blackish brown bar on the 5th 

 and 6th longitudinal rows of the scales. It runs above the base 

 of the pectoral fin and follows the upper border of the opercle 

 to the upper hind-margin of the eye. On both sides, this dark 

 bar is (except on the head) bordered by a very obvious light (in 

 alcohol whitish), bar, the ventral of which is the broadest and 

 about half the width of the dark one. The dorsal middle fine is 

 also dark colored from before the first dorsal fin to the nape. 



This new species is the first known member of the genus 

 Rhomhosoma from the Australian continent. The two previously 

 described species Rh. novae-guineae Ramsay & Ogilby, and 

 lorentzii, have been found in the waters of New Guinea, Aru 

 Islands, and Waigiou. 



Polynemas tetradactylas Shaw. 

 Locality: Roebuck Bay . . . One specimen. 



