from the northern coast of Neio Holland. 177 



work backwards over the orbits. The maxillary lies entirely be- 

 hind the intermaxillary, is less strong and is nearly of equal ^vidth 

 throughout, except that a shoulder projects anteriorly from its 

 upper third. A knob close to its articular condyle projects into 

 the roof of the mouth. The under jaw is still stronger than the 

 upper one, and runs far back, behind the eye, a small heel project- 

 ing beyond its articular canty and forming a point on the side of 

 the gill-membrane. About live pores exist on its fiat under-sur- 

 face. The lips, covering both jaws, are tolerably thick, and of a 

 clear greenish colour even in the dried specimen. The under one 

 folds back on the sides of the jaw, but the fold does not extend 

 round the symphysis. The round eye, having a diameter equal 

 to one-sixth of the length of the head, is placed two diameters 

 behind the tip of the upper jaw, near the profile, but not inter- 

 fering with it, and three cUameters before the gill-opening. Sub- 

 orbital chain narrow, smooth, subtubular, but not distinctly po- 

 rous. The preorbital embraces a quadrant of the orbit, and is 

 wider than the rest of the chain ; its width is increased at its pos- 

 terior end, under the centre of the eye, by a descending corner. 

 Top of the head smooth and rounded off laterally, particularly 

 behind the eye. Cheek large, scaly, quinquelateral. It is bounded 

 above b)^ a line running horizontally between the upper thu'd 

 of the orbit and the upper end of the preoperculum ; posteriorly 

 by the nearly upright, slightly curved, narrow disc of this bone ; 

 inferiorly by nearly one-thu'd of the length of the lower jaw, and 

 anteriorly by the lower half of the maxillary below and the orbit 

 above. Its scales are similar in size and tiling to those of the 

 body. The space bounded by the upper edge of the operculum 

 and the scapular and suprascapular bones is also similarly scaly. 

 The gill-covers and the rest of the head arc clothed with smooth 

 skin. A curve in the upper third of the preoperculum gives its 

 lower part a slight inclination forwards. The interoperculum is 

 parallel to the lower half of the preoperculum and swells into a 

 rounded ridge, whose end appears to form a fulcrum or joint on 

 which the projecting heel of the lower jaw moves. The suboper- 

 culum has a curved exterior edge, a subquadi-ate disc, and the pro- 

 cess which rises before the opcrculun) swelhng into a rounded 

 ridge. The operculum is triangular, with two smooth rounded 

 ridges diverging from its articular angle, one bounding the bone 

 anteriorly, the other running near its upper edge, and ending in 

 a flat, obtuse, slightly projecting tip. The posterior edge of the 

 bone, beneath this tip, has a slight sigmoid flexure. There are 

 no spinous points on any of the bones of the head. The gill-Hap 

 is bordered by membrane, which at its upper part unites with 

 the branchiostegous membrane and the integuments of the hu- 

 meral chain, closing the gill-opening down to the bend of the co- 



