60 THE DISCOBOLI. 



Akatomt. 



No very marked differences from others of the same section of the genus 

 occur in the skeleton of this species. The skull at hand bears a mod- 

 erate occipital crest, and a pronounced ridge across the interorbital space, 

 with others nearly as prominent from the latter toward the ethmoid. The 

 forehead is rather broad, and behind the eyes the crown is nearly quad- 

 rate. In the frontal ridge the curve is intermediate between that of L. cal- 

 liodon and L. mucosus. About half of the greatest length of the suborbital 

 chain equals that of the suborbital spine. A moderate amount of expan- 

 sion obtains in the upper limb of the preoperculum. On the operculum 

 the outlines are comparatively straight. The posterior limb of the suboper- 

 culum is the shorter, thinner, and more flexible. The interoperculum is 

 rather short, and somewhat forward in position ; it is stouter in the middle 

 and more slender backward. Posteriorly the maxilla curves downward ; 

 a little more of it is behind its suborbital angle than in other species. The 

 fan-like plates behind the hindmost vertebra are short and broad, the lower 

 a trifle the shorter ; the lateral ridges indicative of the so called embryonic 

 spine are prominent. In the disk all of the rays are more bent than those 

 figured in Plate VIII. Figs. 12-14; though nearly straight in most of its 

 extent, the anterior ray is sharply turned backward near its inward ex- 

 tremity. It is to be remembered, in making comparisons from these data, 

 that they are taken from an individual of three and a quarter inches. 



The brain is not so much like that of the Cottoid as that of L. Montagui ; 

 it is more elongate, and the difference in size between the hemispheres and 

 the optic lobes is not apparent, while the cerebellum is larger than either. 

 Backward, the last reaches to the prominent posterior lobes ; at its sides, 

 a considerable margin is exposed. Behind the posterior lobes an opening 

 into the ventricle is seen, much as in Plate VIII. Fig. 9. The olfactory 

 nerves are short. The most patent difference between this brain and that 

 of L. Montagui lies in the slightly greater width of the hemispheres as com- 

 pared with the optic lobes, which, with the wider bones of the forward por- 

 tion of the skull, is what might be expected in contrasting with a species 

 having a more pointed head. 



The liver is large ; the median, or lower left, is the largest and longest 

 of the lobes ; the upper lobe of the left side is narrower, and appears as if 

 divided into two lobes ; the riglit lobe is shortest, and nearly as broad as the 



