130 DEEP-SEA FISHES OF THE ATLANTIC BASIN. 



b. Preoral portion of snout nearly equals half its length. Diameter of eye equal to width of 

 interorbital space. Twenty-nine scales of lateral line in front of vent. 



[A. affinis (Giinther). South of Japan.]* 

 2. Snout moderately produced (its length not exceeding postoeular portion of head). 



a. Preoral portion of snout contained 3 times in its entire length. Diameter of eye one-half 



width of interorbital space (two-fifths postoeular portion of head). About 26 scales in 

 lateral line in front of vent A. MACROCHIR (Giinther) 



b. Preoral portion of snout 3J in its length. Diameter of eye less than one-half width of inter- 



orbital space (5 in postoeular portiou of head) A. Goodei (Hill) 



c. Preoral portion of snout 3i in its length. 1 liameter of eyo equal to width of interorbital space 



(3 in postoeular portion of head). Dorsal origin far behind root of ventral. About 20 sub- 

 oval scales in lateral line in front of vent A. piialacrcs (Vaillant) 



d. Preoral portion of snout 4 in its length. Diameter of eye two-thirds width of interorbital space 



(= one-fourth postorbital length of head). Dorsal origin behind root of ventral. About 18 

 scales in lateral line in front of vent. . . [A. MEDIOROSTRIS (Giinther). West of Philippines.] 



e. Preoral portion of snout 2J in its length. Diameter of eye exceeds width of interorbital space 



(=2£ in postorbital length of head). Dorsal origin behind root of ventral. Eighteen to 

 twenty scales in lateral line in front of vent. A slender species; its height 20 J in total 

 length A. gracilis (Goode and P>ean) 



f. Preoral portion of snout about 2 in its length. Diameter of eye equal to width of interorbital 



space (2J in postorbital length of head). Dorsal origin over base of last rays of ventral. 

 Twenty-seven scales in lateral line in front of vent. A stout species; its height 15 J in total 

 length A. pallida (Goode and Bean) 



g. Preoral portion of snout 2 in its length. Diameter of eye greater than the width of inter- 



orbital space (2J in postorbital length of head). Scales of lateral line slightly enlarged. A 



slender species [A. anguilliformis (Alcock). Gulf of Manaar.] 



II. Ventrals united into a broad, flat flake. A rudimentary, keel-like second dorsal. 



Vertex scaly. Scales of lateral line not enlarged. Snout elongate Halosaurichthys, Alcock 



1. Snout produced, its lenth 3 times that of its preoral portion. Diameter of eye greater than 

 width of interorbital space (2 J in postoeular portion of head). 



[H. CAlUNICAUDA, Alcock. Andaman Sea.] 



HALOSAURUS, Johnson. 

 Halosaurus, Johnson, Proc. Zool. Soc. Lond., 1863, 406. 



Body elongate, clothed with cycloid scales ; belly rounded ; tail compressed and tapering 

 to a point. Snout projecting much beyond the mouth, which is nonprotractile and of mod- 

 erate size, with the upper border formed by the premaxillary and maxillary bones, the 

 former small, the latter of moderate size and not reaching beyond the eye, both dentiferous. 

 Teeth in villiform bands, in the jaws, and on the vomer, palatines, and tongue. A short 

 dorsal over the space between the abdominal ventrals and the long anal, which is coalescent 

 with the caudal, the latter consisting of very few rays. Large gill openings. Branchiostegal 

 membrane with numerous rays. Stomach csecal; pyloric creca in moderate number ; a large 

 air bladder. No pseudobranchia?, no barbel nor adipose dorsal. 



HALOSAURUS OWENI, Johnson. (Figure 152.) 



Halosaurus Owcn'i, Johnson, P. Z. S. Lond., 1863, 406, pi. xxxvi, fig. 2.— Gunther, Cat., VII, 428; Chal- 

 lenger Report, 1887, xxu, 236. 



The type, from Madeira, 17 J inches long, was long the only specimen known. 



Snout produced, its preoral portion being nearly one-half of its length. Eye rather 

 large, the length of its diameter being two -fifths of the postoeular portion of the head, and 

 much more than the width of the interorbital space. The maxillary reaches the vertical 

 from the front margin of the eye. The length of the head is more than its distance from 

 the ventral fin, the base of which is entirely in front of and somewhat remote from the 

 base of the dorsal. Pectoral fin with narrow base, very long, extending nearly to the root 

 of the ventral. Scales of the lateral line scarcely larger than the others, without phosphor- 

 escent organs being visible in the only specimen known. Anterior portion of the dorsal fin 

 covered with small scales; anal fin scaleless. Brownish, silvery on the abdomen. (Gunther.) 



* From S. of Japan, Challenger, 565 fathoms, and Andaman Sen, Investigator, 1,000 fathoms. H. Hoskynii, 

 Alcock, is probably the same. 



