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FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



the marginal pair set edgewise, the lower jaw with 

 a pair of marginal plates set edgewise. The gill 

 openings are vertical, set very low down on the 

 sides of the neck, and each is covered with a flap 

 of skin, paralleling the gill cover of bony fishes. 



There are two distinct dorsal fins. The first of 

 these originates about over the gill openings, is 

 triangular, about as high as long, and supported 

 at its anterior margin by a stout spine that is free 

 along the terminal part, with the rear surface of 

 the free part double saw-edged. The second 

 dorsal is separated from the first by a space vari- 

 able in length, and is less than one-third as high 

 as the first, with straight margin. The small 

 caudal fin, marked off from the second dorsal by 

 a deep notch, is lanceolate in shape, ending as a 

 short, whiplike filament; and it extends a short 

 distance forward along the ventral surface of the 

 trunk, there being no separate anal fin. The 

 pelvics and pectorals both have pointed tips, the 

 latter being much the larger and reaching back 

 nearly to the point of origin of the pelvics. The 

 male has a trifid copulatory organ arising from the 

 base of each pelvic fin on the inner side, and also 

 a supplementary bladelike clasping organ close 

 in front of each pelvic fin, its margin armed with 

 4 or 5 hooks, and lying in a pocket from which it 

 can be protruded. The skin is smooth; the lateral- 

 line system is well developed and ramifies over the 

 head in several branches. 



This species is a close ally of the well known 

 chimaera of north European seas (Chimaera 

 monstrosa), but is distinguishable from it by the 

 fact that it has no separate anal fin; that there 

 is a considerable free space between its two dorsal 

 fins; that the outline of the second dorsal fin is 



straight; that its caudal filament is much shorter; 

 and that its pectorals hardly reach back to the 

 pelvics. 



Color. — Lead color, tan-brown or dark sepia 

 below as well as above, except paler on the throat 

 and grayish on the snout. The margin of the 

 first dorsal, the rear and inner margins of the 

 pelvics, and the rear margins of the pectorals are 

 dark. 



Size. — The largest specimen yet reported, taken 

 85 miles off Cape Sable, Nova Scotia, at a depth of 

 between 400 and 500 fathoms, was 49 inches long 

 and weighed 17% pounds dressed. 



General range. — Not uncommon on the conti- 

 nental slope of North America from the latitude 

 of Cape Cod northeastward, along the Nova Scotia 

 Banks, to the Grand Banks, in 160 fathoms to 

 more than 1,200 fathoms; also in the eastern side 

 of the Atlantic off the coast of Portugal. 



Occurrence in the Gulf of Maine. — Our only 

 reason for mentioning this chimaera is that it is 

 (or was) so plentiful along the offshore slopes of 

 the Banks off the eastern part of the Gulf and off 

 Nova Scotia that many were brought in for a 

 few years subsequent to 1875, when fishermen 

 long fining for halibut extended their operations 

 down to 300 fathoms or so. Only one seems to 

 have been reported during the past 25 years, 

 caught off Browns Bank, 85 miles southwest of 

 Cape Sable, between 400 and 500 fathoms on 

 October 15, 1930. 8S But perhaps it would be 

 found no less plentiful now than of old, if sought 

 at the proper depth. The shoalest capture of 

 which we found record was at 160 fathoms. 

 Nothing is known of its way of life nor have its 

 egg cases been seen. 



THE BONY FISHES. CLASS OSTEICHTHYES 

 THE STURGEONS. FAMILY ACIPENSERIDAE 



The sturgeons, like the sharks, have an uneven 

 {"heterocercal") tail with the vertebral column 

 extending out along the upper lobe. But there is 

 no danger of mistaking a sturgeon for a shark for 

 it has only one gill opening on each side, while the 

 gills are enclosed by bony gill covers. And the 

 combination of gills of this kind with sharklike 

 tail and with the fact that the head is covered by 



bony plates united by sutures, sets the sturgeons 

 off from all other Gulf of Maine members of their 

 own class. Two species of sturgeons are known 

 from the Gulf, one of which once was rather 

 common there; the other is extremely scarce 

 everywhere. 



« Reported by Firth, Bull. Boston Soc. Nat. Hist., 61, 1931, p. 9. It was 49 

 inches long and weighed 17H pounds dressed. 



