M. K. Storms 07i the Adhesive Disk ofEcheneis. 75 



of the fossil itself would yield better results. At any rate, its 

 narrowness is what would be expected if the view is adopted 

 that the lamellaj were formed by a gradual transversal enlarge- 

 ment of the bases of the spinous rays and wing-shaped bones 

 accompanied by a reduction of the spines themselves. More- 

 over Dr. Wettstein * speaks of short spines directed back- 

 wards which are observed on the disk of Echeneis gJaronen- 

 sis. If these spines are really spinous rays, and not the inter- 

 neurals, as they may be (if, for instance, the disk is seen from 

 its under surface), then we should have here a strong confir- 

 mation of the views I have adopted. 



111. Finally, in regard to the third question, as to where 

 the disk was formed, evidently the Glaris Echeneis^ showing 

 us the disk still partly on the dorsal region, proves that it was 

 first formed on the back and migrated afterwards towards the 

 extremity of the head. 



It might be objected that, if the disk of Echeneis glaro- 

 nensis does not extend to the extremity of the snout, it is 

 because it is formed of but a small number of lamellae. How- 

 ever, a living species of Echeneis {E. lineata) has pi'obably 

 the same number of Iamella3, notwithstanding which the 

 disk goes to the end of the snout. 



Before leaving this subject I should like to make a few 

 remarks suggested by Echeneis glaronensis — 



1. As to the position in classification of the genus Echeneis ; 



2. As to the general form of the body of Echeneis glaro- 



nensis compared with that of living species. 



1. Authors have classed this genus in various families of 

 Acanthopterygians. J oh. Mliller makes of it a group of the 

 Gobiida3 1; L. Agassiz { and, after him, most authors class 

 them with the Scombrid^. 



Certainly none of the characters of Echeneis glaronensis 

 point towards the Gobiidse ; on the contrary, in the shape of 

 the head, the structure of the ventrals, the size of the pec- 

 torals, the shape of the caudal fin, &c., it differs more from 

 the Gobiidffi than the living forms do. On the other hand, by 

 all these characters and others Echeneis glaronensis ought to 

 be classed among the Cotto-Scombriform Acanthopterygians. 

 But here the difficulty begins. If we adhere strictly to the 

 characters of the families given by Dr. Giinther, Echeneis 



* Ur. Wettstein, loc. cit. p. 82. 



t Johannes Miiller, Abliandl. d. k. Ak. d. Wisseusch. Berlin, 1844, 

 p. 158. 



X L. Agassiz, Ilech. poiss. loss. vol. v. p. 117. 



