354 BONES OF LOPHIUS PISCATORIUS — MORROW. 



slight downward curve, and on the sixteenth it has attained its 

 normal length and angle, and from this, to and including the twen- 

 ty-seventh centrum, the spines gradually decrease in length and 

 angle. The hsemal spine* of the twenty-eighth centrum is much 

 elongated, and is almost parallel with its neural spine, it extends 

 posteriorly beneath the twenty-ninth centrum for two-thirds of 

 the length of the latter. 



On the twenty-ninth centrum there is no hsemal spine, unless 

 a somewhat thick and flattened edge on its posterior extremity, 

 may be said to represent it. In the wing-shaped processes at 

 each side there is a foramen for the vessels, slightly posterior 

 to the termination of the haemal canal proper. 



74 & 75. Dorsal fins. This fish has two dorsal fins, the first 

 containing six spines, two of which are close together and 

 near the nostrils, and are supported by a very peculiar dermal 

 longitudinal spine situated between the turbinal or nasal bones ; 

 looking upon the superior surface of this spine, at its anterior 

 extremity there is a narrow perforated projection which joins 

 the apex of a flat kite-shaped process, the posterior extremity 

 of which terminates in a sharp point curved slightly above the 

 general line of the spine, and beneath which the spine has a 

 flattened superior edge widening to its posterior extremity where 

 it is quite thin and flat. On its anterior half the spine has at 

 its anterior extremity, vertically, a very thin and deep plate, 

 which is strengthened by the flattened edge and process above 

 mentioned ; this thin plate at its anterior inferior extremity is 

 rounded, and curves posteriorly towards the middle of the spine 

 and there disappears. As already mentioned the anterior por- 

 tion of the longitudinal spine lies between the turbinal bones, 

 and its anterior extremity is slightly in advance of the superior 

 processes of the maxillaries ; its posterior extremity extends to 

 nearly the centre of the forks of the frontals. The length of the 

 spine varies in different specimens, a small fish having sometimes 

 a proportionately longer spine than a large one. The spine is 

 enveloped by muscles which control its movements, as well as 



* In one specimen before me, the length of the spine is nearly one and a quarter inches, 

 -while that of the twenty-ninth centrum is one and live eighths inches. 



