Report of a Mission to Guam. 113 



fin; there is a narrow margin of black above this. There is no 

 colored lin^^ at base of dorsal, as in M. lituratus. The anal fin is 

 greenish, with a narrow black margin and the inner third with a 

 wash of brown. Pe(fl:orals and ventrals brownish. This species is 

 closely related to M. lituratus ( Forst. ) , but differs in having a more 

 rounded profile, a decreased number of dorsal and anal ra}"s, a 

 much darker general coloring, without a yellow line at base of 

 dorsal, and with two distinct yellow spots on caudal peduncle sep- 

 arated by a sharply defined black area. These color markings are 

 fixed and distinct in the entire series. This is vmdoubtedl}- the fish 

 figured by Mr. Garrett in "Fisches d. Sudsee," Tafel 28, but it is 

 not the fish described in the text, Vol. I., p. 124, which is a good 

 description of Monoceros lititratics now before me. I have carefully 

 compared a series of these two species of the same size and age,,- 

 and as the differences stated above hold good, even in the details 

 of the markings, I cannot put them under one species. Quoy & 

 Gaimard, description and figure, will not fit either of these species, 

 and I think their species should stand M. carolinarum , Ouo}' & 

 Gaim., until the fishes of the Caroline Islands are better known. 

 Their type specimen Avas eaten, and the figure may be approxi- 

 mately correct. Six specimens, length 3-6 inches. Agaiia, Guam, 

 July, 1900. Hab. Polynesia, Marianas. Tvpe of species is No. 

 216, B. P. B. M. ' 



2,2,2,-2,2,^' Monoceros annulatus (Ouoy & Gaim.). 



Head 4; depth 2.33; eye 2.66; interorbital3; D. vi 27; A. 11 28,- 

 V. I 3. Scales minute, rough. Body compressed and elevated. 

 Forehead with a short projecting horn, situated below the level of 

 the centre of orbits. In specimens 6.50 inches in length the tip 

 end of this horn is equidistant from the orbit and teeth of upper 

 jaw. Its length, measured frona the orbit, 2.33 into head. Teeth 

 .small, fineh' serrate on inner side. The profile from first dorsal 

 spine to tip of snout is slightly convex. Caudal plates absent in 

 young; in specimens 6 inches in length are scarcely visible, and 

 are entirely unkeeled. Color in spirits: Uniform light grayish 

 brown, lighter on the caudal peduncle. Fins dusky, the caudal 

 greenish yellow on the posterior half. Two specimens. Length 

 4-6.50 inches. Agana, Guam, July, 1900. Hab. Western Pacific, 

 Marianas. 



224. Monoceros lituratus (Forst.). 



Head 3.50; depth 2; eye 3.25, 2 into snout; D. vi 30; A. 30; 

 V. I 3; P. 16. Scales minute, rough. Body elevated and com- 

 pressed. Two bony plates on caudal peduncle with short, sharp 

 keels — the yellow coloring of the ba.ses intermingling. The dis- 



O. p. B. p. B. M.— Vol. I., No. 7,. 



