where this commissure leaves the main canal lies anterior and aliglitly mesial to the antero-lateral 

 Corner of the groove on the vertex, and the course of the commissure, on either side, is approximately 

 marked bv the anterior bounding ridge of the groove. This latter ridge begins at the median opening 

 of the commissure and from there runs antero-laterally, immediately posterior to the com- 

 missure, to become confluent with the frontal spinous ridge at the base of the frontal spine, as 

 already described. The frontal and commissural ridges, as well as the three ocular ridges, thus 

 all radiate approximately from the point where the frontal commissure arises from the supraorbital 

 canal. The parietal ridge, also, radiates from this same point; and still another ridge, a slight one, 

 extends from this point, postero-laterally, across the postero-lateral part of the frontal, and leads 

 directly toward but does not quite reach the anterior end of the pterotic spinous ridge, to be later 

 described. There are thus seven ridges radiating approximately from a cerCain point on the dorsal 

 surface of the skull, all of them apparently in some way related to certain of the cranial spines. But 

 what these relations may be, or what the significance of the ridges, I can not determine, excepting 

 that they would seem to indicate some center of formative action at the point from which they radiate. 

 With the exception of the frontal and parietal ridges they seem not to have heretofore been described. 

 The preocular spine, it is to be noted, has two ridges related to it, one on the frontal and the other 

 on the ectethmoid, the latter being the more important. 



In Scorpaena porcus, the comissural ridge runs directly across the bind end of the frontal ridge, 

 this latter ridge abutting against the former one, almost at right angles to it, at a point slightly mesial 

 to the base of the frontal spine and there apparently ending. The commissural ridge and not the frontal 

 ridge thus here bears the frontal spine, the commissural ridge turning sharply backward at its lateral 

 end, and immediately terminating in the backwardly directed spine. This arrangement of ridge and 

 spine is a definite characteristic of all my specimens of Scorpaena porcus, while the former arrange- 

 ment is equally characteristic of all those of my specimens of Scorpaena scrofa in which there are 

 three postfrontal spines, described below. Where there are, in Scorpaena scrofa, but two of these 

 latter spines, the relations of the two ridges here in question, to each other and to the frontal spine, 

 are intermediate in character. 



In addition to the above described spines, all of which are mentioned by Cuvier and Valen- 

 ciennes ('29, vol. 4, p. 291), there are, on the dorsal surface of the head of Scorpaena scrofa, a certain 

 number of other spines, all of which, excepting two, those on the lateral extrascapulars, are also 

 mentioned by Cuvier and Valenciennes. Three of these spines are small, and lie on the postfrontal 

 bone; one near the antero-mesial corner of the bone, one at the postero-mesial corner and one at the 

 postero-lateral corner. The three spines radiate, in general direction, from the antero-lateral corner 

 of the bone, and on that corner there is a small but pronounced tubercle. Joining this tubercle and the 

 antero-mesial spine there is a small but definite ridge, the other two spines having no related ridges. 

 In Scorpaena porcus, in all the specimens examined, there were in this group of postfrontal spines, 

 but one or two spines; the one spine, where it alone was found, being usually bifid. The presence of 

 the three postfrontal spines thus seems to be a definitive characteristic of Scorpaena scrofa, but in 

 certain of my specimens of this fish there are but two spines, as in Scorpaena porcus. These postfrontal 

 spines must be the bifid spines of Jordan & Evermann's ('98) descriptions. 



Postero-mesial to this little group of postfrontal spines, a ridge begins on the pterotic, and 

 running postero-laterally to the bind end of that bone ends in a strong spine. Posterior to, and in 

 the line prolonged of this spinous ridge, a ridge begins on the suprascapular, and running along the 



