The anterior part of the splenial has been fully described in a previous paper. The oval foramen present in the jaws of No. 603 (loc. cit. p. 96) is also present near the symphysis in this individual. (See for., Fig. I.) The suture between the surangular and angular on the external posterior end of the ramus now appears to be accurately determined, as following nearly the course provisionally indicated in the first restoration of the skull and jaws. (See Plate XXXVI.)
Fig. 2 shows how the angular laps over and along the surangular, although the two elements were probably more closely applied than is shown by the cross-section.
The articular appears very similar to those described previously, though perhaps more robust and occupying a more hearly horizontal position in the ramus.
The rami are very slender for their length and height.
Measurements
| No. | 1441. | Greatest length of coronoid, about | 220 | mm. |
| " | 1441. | "width""" | 45 | " |
| " | 1441. | ""posterior end of ramus | 70 | " |
| " | 1441. | """anterior""" | 18 | " |
Thyrohyal.
This specimen, as in No. 878 in the collections of the museum, has the right thyrohyal preserved quite intact. It was retained in the matrix parallel to the inner posterior part of the ramus of that side. The anterior extremity while some- what expanded is more circular in cross-section than was indicated by the element mentioned above. There is evidence of the opposite element in a fragmentary posterior end found in the matrix along the other ramus. Otherwise the shape and proportions are very similar to the thyrohyal of No. 878 described and figured previously.
Sclerotic Plates
Although crushing has badly distorted the sclerotic rings of both orbits there appears to be essentially the same number of plates (14) as observed in other members of this genus. The distortion mentioned above has so displaced the plates 
Fig. 3 Cross-section of the sclerotic plates of Baptanodon natans (No. 1441). One half natural size. that the manner in which they overlap one another is clearly shown. (See Fig. 3)
The plates lap over one another from left to right, the bevelled edge of one over-lapping the reverse bevel of the other. This long free union of the plates would allow the sclerotic ring to expand and contract considerably. One orbit shows the bony covering extending back 40 mm. from the periphery, and it appears quite probable that this covering extended to the very back of the eyeball as in some
