424 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



projecting sjjines or ridges. The occipital depression is very shallow, the occipital 

 ridges depressed, scarcely noticeable, ending in depressed spines which are made 

 out with difficulty. 



Nasal spines undeveloped, the nasal bono small, posteriorly pointed, but not fur- 

 nished with a projecting spine. Upper preopercular spine strongly compressed, 

 curved upward, not reaching opercular margin, its length equaling diameter of eye. 

 No spine at its base in front, as in A. bathybiiis. Below it are two short, strong 

 spines directed downward and backward, and one more slender downward and 

 forward. Opercle with a longitudinal rib ending in a short spinous jioint. A short 

 spine on angle of opercle, and one below it on Interopercle. Mucous canals every- 

 where greatly enlarged, giving a spongy texture to the entire head ; series of very 

 conspicuous pores on the preopercle, the mandible, and below suborbital chain. 



Head 2| in length; depth 5. Dorsal vii-13; anal 10 or 11; pectoral 17 or 18; 

 ventral i, 3. Lateral line with 17 pores. 



Mouth broad, oblique, maxillary reaching middle of pupil, 2^ in head. Mandible 

 slightly protruding. Minute teeth in upper jaw anteriorly in two rather distinct 

 rows, laterally in narrow bands. Teeth ou vomer, none on the palatines. Eye 

 longer than snout, 3f to 4 in head. Interorbital width one-half diameter of orbit. 

 Gill-membranes widely joined, with a wide, free posterior edge. No slit or pore 

 behind last gill. Body smooth, without plates, granulations, or filaments. No 

 plates developed in connection with the lateral line. Fores of lateral line in a double 

 series ; the two closely approximated, those of the lower series much the largest. 

 Longest rays of second dorsal half length of head, twice the longest dorsal spine. 

 Pectoral reaching front of anal or slightly beyond. Ventrals short, not nearly 

 reaching vent. Upper parts very light-brownish, the belly and sides below lateral 

 lines dark brown. Fins blackish. Mouth and gill-cavity dark. 



Three specimens, 49 to 55 mm. long, from station 3329, north of Unalaska Island; 

 depth 399 fathoms. 



66. Gymnacanthus pistilliger (Pallas). 



We agree entirely with Dr. Bean aud Mr. Dresel (Proc. U. S. Nat. Mus. 1884, 251) in 

 considering the North Pacitic species, G. pistilliger, distinct from the North Atlantic 

 form, G. tricuspis. We have not had an opportunity to make direct comparison 

 between the two, but find the following difl'erences on com})aring our specimens with 

 the current descriptions of G. tricuspis. G. pistillvjer has a different fin formula, 

 the spines and rays of dorsal and anal fins being fewer in number. This is shown 

 bj' the following table, based on an examination of 40 specimens : 



The normal formula may therefore be given : Dorsal ix or x-13 to 15 ; anal 15 to 17. 

 The type of G. pistilliger is said to have dorsal ix-13; anal 16; and its synonyms, 

 G. ventralis Cuvier «Ss Valenciennes and G. intermedius Temminck A: Schlegel, have 

 respectively dorsal ix-13, anal 17, and dorsal ix-13, anal 14. 



In G. tricuspis, the formula is dorsal xi or xii (rarely x)-15 to 17; anal 16 to 19. 



The dorsal fins are more widely separated in G. pistilliger, where the interspace is 

 equal to half or more than half the diameter of the pupil. 



The vertebra' are fewer in number, 12-|-24, instead of 12-f-28. 



In G. pistilliger an obtuse prominence above the hinder margin of orbit bears in 

 young individuals a slender cirrus, which frequently disappears in adults. Behind 

 the eye a continuous occipital ridge bears three smaller bony prominences, the first 



