2006 Bulletin //, United States National Museum. 



741. GYMNOCANTHUS, Swainson. 



Gymnocanthus, SWAINSON, Class. Fish., etc., n, 271, 1839 (ventralis). 



Phobetor, KROYER, Naturh. Tidschr., i, 263, 1844 (tricuspis). 



Elaphocottus, SAUVAOE, Nouv. Arch. Mus. Paris (2), I, 1878, 142 (pistilliger). 



General characters and appearance of Acantliocottns, but with no teeth 

 on the vomer, the slit behind the last gill small or wanting; upper pre- 

 opercular spine stout, armed with 2 or 3 antler-like processes ; fins all very 

 large, the yen trals notably so. Arctic Seas, (yv^rdg, naked; anavQa, 

 spine.) 

 a. Interorbital space not anhed with bony granulations; males with a round white 



spot on belly ; last gill arch without slit or pore. 



6. Dorsal rays X, 14 or 15; anal 16; a cirrus behind eye in young; occipital ridge 



with 3 bony prominences ; axial region in male with fringed filaments, white 



at tip. PISTILLIGER, 2375. 



66. Dorsal rays XII, 16; anal 18; no cirrus behind eye; occiput without bony 



prominences; axial region without fringed filaments in either sex. 



TRICUSPIS, 2376. 



aa. Interorbital region covered with bony granulations ; males without white spots on 

 belly ; dorsal rays XI, 16 ; anal 19. GALEATUS, 2377. 



2375. GYMNOCAIVTHUS PISTILLIGER (Pallas). 



Dr. Gilbert describes this species as follows : 



"Compared with Gymnocantlms tricuspis, G. pistilliger has a different fin 

 formula, the spines and rays of dorsal and anal fins being fewer in number. 

 This is shown by the following table, based on an examination of 40 

 specimens : 



" The normal formula may therefore be given : D. IX or X, 14 or 15 ; A. 16 

 or 17. The type of G. pistilliger is said to have D. IX, 13; A. 16; and its 

 synonyms, G. ventralis, Cuvier & Valenciennes, and G. intermedius, Tem- 

 minck & Schlegel, have, respectively, D. IX, 13; A. 17; and D. IX, 13; A. 14. 

 In G. tricuspis the formula is D. XI or XII (rarely X), 15 to 17; A. 16 to 19. 

 The dorsal fins are more widely separated in G. pistilliger, where the inter- 

 space is equal to | or more than | the diameter of the pupil. The verte- 

 bra are fewer in number, 12 + 24 instead of 12 + 28. In G. pistilliger an 

 obtuse prominence above hinder margin of orbit bears in young indi- 

 viduals a slender cirrus, which frequently disappears in adults. Behind 

 the eye, a continuous occipital ridge bears 3 smaller bony prominences, 

 the first immediately behind the eye, the second and third approximated 

 at posterior end of ridge ; these bear no cirri. G. tricuspis has 110 tubercles 

 on occiput. In males of G. pistilliger, the post axial region is furnished 

 with a number of very slender filaments, each of which is expanded at tip 



