14 Watson & Day, Notes on some Palceozoic FisJies. 



head, largely as a cast in gypsum of cavities left in the 

 ironstone by the decay of the cartilage. This specimen 

 shows us that there is a large cartilaginous cranium lying 

 to a considerable extent below the parietals but extending 

 far forward into the ethmoidal region. So incompletely is 

 it exposed that our account of it can only be very slight. 

 As exhibited it shows at its extreme posterior end a 

 narrow dorsal surface over the cerebellar region which 

 suddenly expands to form a pair of ridges presumably 

 housing the posterior vertical semicircular canals. For- 

 ward of this region the upper surface is essentially flat 

 and is closely applied to the under surfaces of the 

 parietals and " supratemporals." The lateral borders are 

 produced in powerful and somewhat lengthy processes, 

 with the outer ends of which the hyomandibulars articu- 

 late. From here the brain case rapidly narrows, until 

 between the orbits it is far higher than wide. It then 

 expands again slightly in the ethmoidal region. 



The palate is incompletely but satisfactorily exposed 

 in this specimen. The large pterygoidal element resembles 

 in its structure that which we have already described in 

 Glyptopomus, but the vertical part of the bone which in 

 that form is shown to lie behind the articulation with the 

 parasphenoid here rises to the top of the skull, so as 

 nearly or quite to come into contact with the cranial roof. 

 The posterior end of the bone is clearly shown to be 

 deflected outwards to surround the quadrate, the extreme 

 tip of which is visible and whose position is certain from 

 the known structure of the articular of the lower jaw, 

 which is still in natural articulation with it. The speci- 

 men leaves it uncertain whether the ectopterygoid and 

 palatine are really separate bones or are fused as in 

 Megalichthys. The specimen rather suggests that the 

 ectopterygoid is fused whilst the narrow palatine retains 



