298 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [88] 



suckers grade gradually iuto the large or primary ones, both in size and 

 form ; they are, however, armed with four or five very sharp incurved 

 teeth on the outer margin, of which the median one is longest, while 

 the inner margin is usually entire. They are very oblique and one-sided 

 in form. The membrane around the rim of all the suckers is thickened, 

 but most so on the basal ones; it usually recedes behind the large median 

 tooth, leaving there an emargination. 



The outer buccal membrane is not very large ; its inner surface is 

 closely covered with lamelliform folds and wrinkles; its border is pro- 

 longed into seven acute angles, from which membranes extend to the 

 opposite arms, going to the upper sides of the second and fourth pairs 

 of arms, and to the lower side of the third pair; but the seventh angle 

 is in the median dorsal line, and the membrane from it bifurcates, one- 

 half going to the inner side of each dorsal arm. Immediately around 

 the jaws there is a circular, thickened, rugose oral membrane, with a 

 strongly lobed edge, while its inner surface is radially wrinkled and 

 covered with scattered rounded verrucre. A plain fold intervenes be- 

 tween this and the outer buccal membranes. The beak and pharynx 

 can be protruded its whole length, when in use. At such times the oral 

 membranes are partially unfolded. 



The jaws are sharp and incurved at tip, reddish brown to brownish 

 black in color, with the posterior borders of the laminae whitish and 

 translucent. The upper mandible has a much incurved tip, with the 

 cutting edges regularly curved, and with a shallow notch at their bases, 

 beyond which the anterior edges rise into a broad, obtuse lobe or low 

 tooth, by which the hardened and dark-colored part, as seen by trans- 

 mitted light, has the form of a sharp angular tooth, but its actual pro- 

 jection anteriorly is but slight, because the translucent edge beyond it 

 rises to about the same level. The lateral-posterior borders of the 

 frontal laminae are sinuous and incurved in the middle; the palatine 

 lamina is broad, with the posterior lateral edges incurved and sinuous. 



The lower mandible has the extreme tip strongly incurved, forming a 

 slight notch close to the tip, below which the edges are slightly incurved 

 or nearly straight, with a decided V-shaped notch at the base; the an- 

 terior edges, beyond the notch, form a triangular tooth of the inner 

 laminre, but this is obscured, unless viewed by transmitted light, by the 

 outer alar lamina, which rises at its anterior edge, where it is translu- 

 cent, nearly to a level with the tooth; the inner ends of the ahe are wider 

 than the middle, and broadly rounded ; the gular lamina? are short, nar- 

 rowed posteriorly, with their inner edges incurved, and with a thickened, 

 prominent ventral carina. 



The jaws of a large specimen measure as follows: Upper mandible, tip 

 to posterior end of palatine lamina, 22 nm ; to dorsal end of frontal lamina, 

 16 mm ; to posterior lateral edge of same, 9 mm ; to base of cutting edge, 5 mm ; 

 inner edge of palatine lamina to dorsal end of frontal lamina, 17 mm ; lower 

 mandible, tip to inner end of alse, 13 nim ; to ventral notch of ahe, 4 ul,n ; 



