542 MR. T. GOODEY OX THE SKELETAL | Mar. 15, 



III. The Skull, Visceral Arches, etc. 

 (Plates XLIL, XLIII. figs. 1-6.) 



My observations on two skulls agree in the more important 

 points with the description given by Garman (10) pp. 7-9. It 

 is not my intention in the present account to redescribe the 

 wbole of the structure, but rather to amplify the original de- 

 scription in those points which appear to call for special emphasis, 

 and to make certain additions. I propose to deal first with the 

 cranium, then with the first and second visceral arches and their 

 ligaments, and finally with the branchial skeleton and certain 

 other points. 



a. Cranium (fig. 1). 



At the extreme anterior end of the cranium is the broad, 

 flat, and somewhat rounded rostrum (r.), which is notched at its 

 sides. Its shape gives to the nasal region a curious truncated 

 appearance. The olfactory capsules (o.c.) are large, rounded, and 

 thin-walled. Their large apertures have the nasal cartilages (lie.) 

 fitting into them. Each of these is ring-like and has a bar 

 across the middle of the aperture so as to give rise to the double 

 opening which each capsule presents in external appearance. 



The anterior fontanelle {a.f.) is very large and broad, extending 

 posteriorly to a point almost level with the preorbital process. 

 Immediately behind the olfactory capsule is a deep furrow which 

 communicates above with the foramen transmitting the ophthal- 

 micus branch of the seventh nerve, and in which are found 

 branches of the latter nerve. Posterior to this furrow is a some- 

 what prominent ridge having a sharp edge orbitally, and gradually 

 running into the tapering backwardly directed preorbital process 

 below. On the anterior side of the orbit is a very smooth, hollow 

 surface, against which the eyeball rolls. On the cranial wall at 

 the anterior end of the orbit is developed a rather prominent 

 articular surface which receives the inner side of the ethmo- 

 palatine process of the palatoquadrate cartilage. 



The supraorbital ridge is somewhat thin and prominent. In 

 the shallow groove along its dorsal surface are a number of 

 foramina which transmit branches of the ophthalmicus branch of 

 the seventh nerve supplying the supraorbital sensory canal. 



Garman described the postorbital process (po.p.)&s of irregular 

 shape and moderate breadth. In the specimen which I have 

 examined it appears to be quite regular in outline. It is a back- 

 wardly curved, stoutish process, gradually tapering towards its 

 rounded end. On its upper surface are found a number of 

 foramina which also transmit branches of the seventh nerve to 

 the sensory canal-system. 



From the median vertical longitudinal section of the cranium 

 (fig. 2), it is seen that the notochord is continued as a thin strand 

 of tissue in the basis cranii as far forward as the pituitary fossa. 



