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854 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 
at tip. The other teeth are very similar to each other, six in number on 
each side and slightly increasing in size from the middle. They are 
much broader than high, and armed with about four sharp points turned 
outward, besides one or two smaller ones. The first point is longest, 
and has a small cusp on its side, so that strictly one might call the 
second cusp longest. 
Gill-openings 7, high ; pectorals moderate, truncate and slightly con- 
cave behind; ventrals moderate, rather backward; anal small, the single 
small dorsal just in front of it, covering most of the interspace between 
it and the ventrals. 
Tail very long, forming a little more than one-third the length (22 
A notch near i tip below; the lower lobe a little developed. Wpue 
edge of tail with about jones series of scales, much enlarged, so that its 
entire edge is finely serrated. 
Described from two specimens from Soquel, each 18 inches long, one 
male, the other female. 
Description of the jaws of Heptranchias maculatus, adult, from Humboldt 
Bay. 
No median tooth in upper jaw. Upper jaw with two transverse 
series of teeth on each side of symphysis, the outer series usually with 
two, the inner with four or five teeth, some of which are placed 
externally to the main row. They are lanceolate from a quadrate 
base, the points directed backwards and curved slightly outwards, 
without cusps or serrations. First tooth of main series similar to sym- 
physeal teeth, but larger and broader, with a larger or smaller cusp at 
dbase on outer side and with or without minute serrations on base of 
inner side; from this towards corner of mouth there is much variation 
in the development of cusps and serratures, the teeth, however, con- 
stantly approximating in shape those of the lower jaw, always differing 
in being smaller, with external margins more inclined, and with the 
central cusp larger in comparison to others and more distant from 
them. Sometimes on each side are four or five teeth, bicuspidate and 
without serrations on inner edge; in other jaws the second or third 
tooth trom symphysis has three or more cusps on the outer margin, and 
with serrulations or a single cusp at base on inner side. The last large 
tooth on each side usually broad and low, with the two margins sub- 
equal, without prominent median cusp; the inner margin minutely 
serrate; the outer with seven or eight cusps. 
In lower jaw the teeth are much larger than in upper, and are uniform 
in shape and style of armature; they are wide from a quadrate base, the 
outer margins comparatively little inelined and with the cusps regularly 
and rapidly graduated, usually seven in number; the inner margins 
short, gibbous and much curved, always distinetly serrate ; median tooth 
upright, without median cusp, and with three or four cusps on each margin. 
Each jaw has laterally about 12 transverse series of small linear teeth, 
