1899.] sxEUCTUEE OF labobdb's shakk. 733 



of which the dimensions are given in the British Museum Catalogue 

 of Fishes (vol. viii. p. 428), being a little less than 10 inches in 

 length measured from the extremity of the snout to the tip of the 

 upper lobe of the caudal. The skin, as in the British Museum 

 individuals, is, regarded as a whole, of a uniform brownish-black 

 colour, but while the proximal portion of the azygos and paired 

 fins are of the same tint, the distal present a marked contrast, 

 being of a dull yellowish hue. There is a well-marked mid-dorsal 

 and an equally well-marked mid-ventral groove, and on either side, 

 not far from the dorsal surface, a rather deep lateral groove runs 

 backward nearly to the base of the caudal. The area occupied by the 

 five branchial apertures is about 8 mm. in length, the last of the slits 

 being immediately in front of the base of the pectoral. The 

 individual gill-slits are very small (only 2 millimetres in length), 

 while the spiracles, on the other hand, are noteworthy for their 

 large size ; semicircular in outhne, they measure 5 millimetres 

 along the posterior border. 



On the upper surface of the head are two well-marked curved 

 longitudinal grooves, continuations forward of the lateral grooves 

 already mentioned, connected by a transverse one situated imme- 

 diately between the spiracles. Each of these grooves exhibits a 

 series of pores (the openings of mucus-canals) which can be craced 

 backward for some distance along the sides of the body. A row 

 of pores further passes from the longitudinal groove of either side 

 obliquely downward between the spiracle and the eye, and a 

 second transverse row runs between the eye and the nostril to 

 join a third row situated at right angles at some distance below 

 the level of the eye. Additional pores more scattered in distri- 

 bution occur in tlie skin covering the upper, and also in a less 

 degree in that clothing the lower jaw. 



The naves occupy a considerable area near the tip of the snout, 

 being removed from the mouth by a considerable interval. Their 

 upper portion is rounded, and they are continued ventraliy in the 

 form of elongated slits overlapped by a valve of skin. The ei/es 

 are large, measuring 9 mm. in antero-posterior diameter. 



The scales are very small, communicaring a minutely granular 

 appearance to the skin, which is almost smooth, there being hardly 

 any perceptible harshness to the feel when the fingers are passed 

 along it from head to tail or vice versa. Magnified a few diameters 

 they appear in the form of slightly angular papillae. When 

 isolated, after boiling a fragment in caustic potash, they exhibit 

 irregularly lozeuge-shaped outlines and possess an elevated central 

 and a depressed marginal area with a slightly toothed edge. 



The aperture of the mouth at first sight appears much more 

 extensive than it actually is, owing to a deep groove which runs 

 backward from each angle. In the lower jaw only a single row 

 of teeth are present. As noticed in Dr. Giinther's excellent 

 diagnostic description, they are of considerable size, triangular in 

 outline and non-serrated. The teeth of the upper jaw are much 

 smaller, conical, and are disposed in three series. 



