1898-1902. No. 33.] UPPER DEVONIAN FISH REMAINS. 



Macropetalichthys Scheii new species. 

 (PI. I, fig. 1-6). 



One of tfie most interesting specimens in my material from Elles- 

 mere Land is a cranial shield belonging to a new, small form of tlie 

 rare genus Macropetalichthys. Unfortunately only one specimen has 

 been found (S. 1. 107). Even this is not perfectly preserved. It shows 

 comparatively well the hinder portion of the head as far forward as the 

 formost rim of the orbits, but is otherwise defective. The main features 

 of the head, however, can be reconstructed. 



General Description. A small form with an extended 

 oval cranial shield, and very large, extended orbits; the sensory canal 

 system shows at the extreme rear a rudimentary lateral line and opens 

 with only one series of outer pores; supraorbital angle about 40 «. 



Description. 



Dimensions. The following measurements are determinable 

 upon the specimen before us : 



1. Length from the posterior edge of the cranium to the supraorbital 

 commissure .28 mm. 



2. Length from the posterior edge of the cranium to a line 

 between the posterior rim of the orbits . .... 35 — 



3. Length from the posterior edge of the cranium to aline 

 between the points in front of the oi'bits where the supra- 

 orbital canals bend forward . .4.5 — 



4. Breadth of the head at the supraorbital commissure . . 36 — 



5. Distance between the orbits ... . . .... 14.5 — 



6. Length of the orbits ... .... . 11.5 — 



7. Probable breadth of the orbits . 7.5 — 



The length of the head cannot be determined with complete exac- 

 titude as the snout portion is missing. However the left supraorbital 

 canal can be traced forwards for a distance of 6 mm. in a slightly 

 convergent direction. It appears, therefore, that we may estimate the 

 total length of the head at about 55 mm. 



Form. The cranial shield appears to have preserved its form 

 quite well. As mentioned above, it is about 55 mm. in length and 

 36 mm. in breadth. The length divided by the breadth is thus about 1.5. 

 As the central and posterior portions are considerably arched, the breadth 

 might increase to about 45 mm. if the specimen were pressed flat. 



