THE DISCOBOLI. 69 



twenty-two of the anterior rays of the dorsal are segmented. All of the 

 bones are less solid than those of L. mucosus. Seen from above, the sides 

 of the skull are nearly parallel, the snout being about as wide as the occiput. 

 The crown is flattened ; the occipital crest is moderately prominent ; the 

 ridges are low and not very conspicuous; the frontal ridge apparently is 

 interrupted in the middle of the interorbital space, to be supplemented by 

 a short transverse ridge a little distance farther back ; and the ridges behind 

 the turbinals are approximately parallel. In the formation of the overhang- 

 ing snout, the intermaxillary has been modified very little; it retains the 

 shape and position of the superior process, toward the ethmoid, of the other 

 species ; but the more important elements of the bony foundation appear to 

 be secured by the forward projection and greater development of the subor- 

 bitals, the turbinals, the palatines, and the maxilla?, accompanied by a slight 

 retraction of the mouth through the assumption by the lower end of the 

 suspensorium of a more backward position. As the snout has been widened, 

 the forward ends of the maxilla? have been considerably extended toward 

 the median line of the skull. A tough spongy tissue upon the rostral 

 bones seems to confirm the idea of utilization in pushing, scraping, or 

 digging. The suborbital spine is nearly half of the greatest length of the 

 chain. The amount of expansion in the upper limb of the preoperculum 

 is hardly as great as in that of L. calliodon. The lower end of the hyo- 

 mandibular being so far backward, the bend in the preoperculum has become 

 almost right-angled. Very slender postorbitals connect the suborbital spines 

 with the postfrontals. In the operculum a close resemblance is seen to that 

 of L. Agassizii, Plate III. Fig. 2. The anterior section of the suboperculum 

 is slender and spine-like; the posterior is membranous. Posteriorly, about 

 two fifths of the interoperculum is slender and bent upward ; anteriorly, it is 

 stouter. Compared with those of L. mucosus the teeth are small ; the cusps 

 are acute subcorneal. 



The entire brain, Plate VIII. Figs. 4-6, is rather elongate ; owing to the 

 narrowness of the optic lobes, the Cottoid resemblance is not so manifest. 

 Hemispheres, optic lobes, and cerebellum are nearly equal in size. The 

 posterior lobes are decidedly prominent, and are not quite reached by the 

 cerebellum. The olfactory lobes are well developed ; the olfactory nerves 

 are short and widely divergent forward, as in L. Montagui, Plate VIII. 

 Fig. 9. 



The liver is peculiar in having a long narrow upper lobe on the left. 



