352 ACRONURIDJE. 



lines. 



Length of the nineteenth vertebra 3| 



of the twenty-first vertebra 21 



of the abdominal portion 22 



of the caudal portion 50 



of the eleventh neural spiae 8 



Width of the cui've of the hoemal bone 26 



5. Naseus olivaceus. 



Chaetodon olivaceus, Solander, MS. Brit. Mus. with figure. 

 Naseus olivaceus, Cuv. 8f Val. x. p. 288. 



30-28 28-29 



Forehead with a more or less projecting protuberance opposite to 

 the upper half of the orbit. The snout is moderately produced, with 

 the upper profile rather concave ; the length of that profile is about 

 twice the distance of the orbit from the dorsal fin. Teeth very slightly 

 compressed, tapering at the extremity, about thirteen on each side of 

 the upper jaw. The height of the body is one-half of the total length 

 (the caudal fin not included). The length of the fifth dorsal spine 

 equals its distance from the first. Caudal plates rather small. 

 Greyish-ohve : base of the caudal plates blue ; dorsal fin with two 

 series of whitish dots ; anal with two longitudinal lines along the 

 middle. 



Otaheiti. Philippine Islands. 



a. Four inches long. Otaheiti. — Type of the species. D. ^, A. ^. 



Scarcely any frontal protuberance. 



b. Six ruches and a half long. Philippine Islands. From Mr. 



Cuming's Collection. — D. ^, A. ^. Frontal protuberance just 

 conspicuous. 



c. Stulfed : ten inches long. — D. ^, A. ^. 'Frontal protuberance 



two lines long. 



6. Naseus annulatus. 



Priodon annulatus, Quoi/ 1^ Gaim. Voy. Uran. Zool. p. 377 (yoimg). 



Naseus marginatus, Cuv. 8f Val. x. p. 280 (adult). 



Priodon annidaris, Cuv. 4" Val. x. p. 302. pi. 294 (young) ; Bleek. 



Aviboina, ii. p. 558. 

 Naseus annulatus, Bleek. Celeb, viii. p. 304. 



D-S- ^-2^ C^c.pylor.5. 

 Forehead with a more or less projecting protuberance, situated 

 below the level of the centre of the orbits. The snout is moderately 

 produced. Teeth very small, with a very fine serrature on the apical 

 half. The length of the fifth spine is nearly equal to its distance 

 from the first. Caudal plates very small, scarcely keeled, and in 

 j^oung individuals absent. Brown : anal with one or two bluish 

 longitudinal bands ; dorsal and anal -with a narrow, caudal with a 



