442 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



23. COELORHYNCHUS TKOMPSONI, new species. 



Type-specimen. — Cat. No. 78214, U.S.N.M., a mature female 106 

 mm. long to anus, dredged at Albatross station 5363, at a depth of 180 

 fathoms, in Balayan Bay, on the southwest coast of Luzon. 



Four other specimens were obtained : 



Albatross 

 station. 



5110 

 5118 



5518 



Locality. 



Depth in 

 fathoms. 



< 'hina Sea, 01T southern Luzon I 135 



Verde Island Passage, Luzon 159 



Off northern Mindanao 200 



Bottom 

 tempera- 

 ture. 



Number 

 of speci- 

 mens. 



' F. 

 59.0 



54.0 



The two specimens from station 5518 show certain differences 

 from the typical specimens, and are referred with some doubt to 

 the same species. It is of interest to note in this connection that 

 all of the 14 specimens of the preceding species, C. quincunciatus, 

 were dredged at six stations among the islands between the localities 

 at which typical and aberrant specimens of C. thompsoni were ob- 

 tained. The aberrant specimens differ in the rougher spination 

 of the scales, in the fewer pyloric caeca (14 instead of 22), and in 

 the slightly narrower interorbital and suborbital. 



Fin-rays — first dorsal, II, 9; pectorals, 15-16 (17 or 18); ven- 

 trals, 7. 



Greatest depth of body, 2.2 (2.3 to 2.4) in head; width across pec- 

 toral bases, 3.3 (3.3 to 3.7). The sides of the snout gradually con- 

 verge forward toward the very sharply acuminate tip, which, 

 higher than in C. argentatus or C. quincunciatus, lies on a horizon- 

 tal passing through the eye above the lower margin of the pupil. 

 The greater convexity of the dorsal outline of the snout, together 

 with other characters, renders the physiognomy of this species very 

 different from that of C. argentatus and C. quincunciatus, which 

 are quite similar in their general appearance. The preocular length 

 of the snout is contained 2.2 (2.1 to 2.15) times in the head; preoral 

 length, 2.35 (2.23 to 2.3) ; width of snout at front of orbits, 3.5 

 (3.3 to 3.6) ; width of snout at anterolateral angles (a point below 

 the front of the nasal fossa), 1.5 (1.4 to 1.55) in the distance 

 anterior to that point (in other words, in the ethmoid region of the 

 infraorbital ridge). The occipital ridges diverge strongly anteri- 

 orly, but weakly posteriorly ; the least distance between them is 

 contained 2.4 (2.5 to 2.65) times in the interorbital width; from 

 their terminations on each side a scaleless groove extends back- 

 ward to the lateral line. The sharp postorbital ridge curves slightly 

 downward behind the preopercular ridge; the subopercular angle 



