GONOSTOMATIDAE 283 



width. Second suborbital greatly enlarged, covering entire cheek. Vomer toothless. 

 The whole body covered with thin cycloid scales; about 36 in a longitudinal series. 



10 or II gill-rakers on lower part of anterior arch. Dorsal 14-16 (17); origin about 

 equidistant from root of pectoral and base of caudal. Adipose fin rather small. Anal 

 29-31 ; origin opposite to that of dorsal. Pectoral with 11 or 12 rays. Pelvic 8; origin 

 equidistant from tip of lower jaw and base of caudal or a little nearer the former. A pair 

 of photophores at the symphysis of the mandibles, and a series of nine between the 

 branchiostegal rays ; a single photophore in front of the lower corner of the orbit ; a 

 narrow vertical streak in front of the operculum, with one luminous spot above and two 

 below; three larger luminous patches at base of caudal fiin, one above and two below; 

 lower series of photophores on body consisting of 5 in front of the pectoral fin, 10 or 



11 from pectoral to pelvic, 5 from pelvic to origin of anal, and 17-19 from anal to base 

 of caudal; in the upper series there are 13- 15(1 + 9+3 + 0-2). 



Described from 18 specimens, 28 to 140 mm. in length. 



Hah. Mediterranean and Eastern Atlantic.^ 



Two distinct sub-species of Gonostoma denudatum may be recognised, and the main 

 differences between them have already been pointed out by Jespersen and Taning.^ 

 The true de?mdatum occurs in the Mediterranean and in the neighbouring parts of the 

 Atlantic; the specimen from Madeira described by Johnson belongs to this sub-species. 

 The other, which may be called allanticum (n.subsp.), occurs only in the Eastern 

 Atlantic, and may be recognised chiefly by the greater number of gill-rakers and by the 

 arrangement of the photophores above the origin of the anal fin. The dorsal fin seems 

 to be inserted a little further forward in this form, but my material is not sufficient to be 

 certain of this. The two sub-species may be recognised as follows: — 



I. Usually 5+10 gill-rakers on the first arch ; first two photophores above the anal fin placed much 

 higher than the two which follow, which are themselves situated lower than the remainder. 



denudatum 



II. Usually 6+ II gill-rakers on the first arch; all the anterior photophores above the anal fin 

 forming an unbroken series at about the same level. atlanticum 



Gonostoma elongatum, GUnther. 



Gonostoma elongatum, Giinther, 1878, Ann. Mag. Nat. Hist. (5) 11, p. 187; 18S7, Deep-Sea Fish. 



'ChaUenger\ p. 173, pi. xlv, fig. B; Alcock, 1891, Ann. Mag. Nat. Hist. (6) viii, p. 127; 1892, 



ibid. (6) X, p. 354; Brauer, 1906, ' Valdivia' Tiefsee-Fische, p. 75, pi. iv, fig. 4; Weber, 1913, 



' Stboga' Fische, p. 17; Weber and Beaufort, 1913, Fish. Indo-Austral. Arch. 11, p. 122, fig. 45. 



Sigmops stigmaticus, Gill, 1884, Proc. U.S. Nat. Mus. vi (1883), p. 256. 



Neostoma elongatum, Collett, 1896, Bull. Soc. zool. France, xxi, p. 96. 



Cyclothone elongata, Goode and Bean, 1895, Ocean. Ichth. p. loi, fig. 119; Alcock, 1899, Cat. 



Indian Deep-Sea Fish. p. 139. 



Cyclothone (Sigmops) elongata, Jordan and Evermann, iSg6,Bull. U.S. Nat. Mus. xlvii (i), p. 583. 



1 According to Goode and Bean this species was taken in the Western Atlantic off the New England coast 

 in 1881, and from off the Californian coast by the ' Albatross'. These specimens have not yet been described. 

 ^ I am greatly indebted to Mr A. V. Taning for notes on these sub-species. 



