450 PKOCEEDIKGS OF THE GEOLOaiCAL SOCIETY. [DcC. 15 



temal scutes on each side are somewhat bent up towards the dorsal 

 surface ; but in this, as in other specimens, the outer margins of 

 these scutes thin out, and exhibit not the least sign of having been 

 connected with any other. In this respect there is a marked contrast 

 between the outer and the inner edges. 



There are six longitudinal rows in this specimen, which is the 

 number assigned by Geo&roj St.-Hilaire (supra, p. 448) to the Teleo- 

 sauria generally. Six exist, as we have seen, in T. temporalis. 

 Dr. "Wagner found only five in his specimens of the ventral shield 

 of T. Cadomensis ; but, as he states, it was imperfect. Six are, as 

 I have pointed out, represented by Cuvier in T. Cadomensis, and the 

 same number is shown in the figure, given by Bronn and Kaup, of 

 Pelagosaurus typ>us. These authors state that there are ten longi- 

 tudinal rows of scutes in the dermal armour of Mystriosaurus 

 longipes ; but their figures and description make me think that this is 

 a hypothetical conclusion, and that what they have seen and figured 

 is only the ventral armour, with its six rows of plates. 



I cannot ascertain from Prof. Owen's description what is the pre- 

 cise number of longitudinal series of " lateral and ventral " scutes in 

 Teleosaurus Chajymanni. They are said to be " more perfect squares 

 than those next the spine," and to have no keels. In these respects 

 they obviously agree with the corresponding scutes of the Teleosauria ; 

 but it is stated that " the median abdominal scutes are not opposite 

 but alternate ; their median margins are rounded oif or slightly an- 

 gular ; and, while the anterior part of that margin is overlapped by 

 the posterior half of the opposite scute in advance, the posterior 

 half overlaps the succeeding scutum of the opposite side." This 

 description would apply much better to the sutures between a 

 median series and that which foUows it externally, than to the 

 junction between the two median series of scutes, which are always 

 opposite in the Teleosauria I have examined. 



The internal faces of the dorsal scutes of the Teleosauria are 

 concave from side to side, and convex from before backwards ; they 

 may be smooth or carinated, but the ventral scutes appear to be 

 always flat and without a keel. 



Comparison of the Scutes of Stagonolejpis with those of Crocodilia 

 and Teleosauria. — Bearing in mind the features of the dermal armour 

 of the Crocodilia which have just been detailed, it becomes no diffi- 

 cult matter at once to find an analogue for each kind of scute found 

 in Stagonolepis. The jiat scutes are strictly comparable to those of 

 the ventral shield of the Teleosauria, the hroad and the thich angu- 

 lated scutes to the dorsal scutes of the same Crocodilians, while the 

 irregular angulated scutes are very similar to the dermal bones, which 

 are scattered between the margins of the dorsal and cervical shields 

 of the existing Crocodiles. 



At this stage of the inquiry, the full meaning of a piece of evidence, 

 whose value I had, up tiU then, but very imperfectly recognized, 

 became obvious. This was a remarkable natural cast, obtained by 

 Mr. Patrick Duff, at Findrassie, and which had been sawn through 

 longitudinally by that gentleman's direction, so as to expose its 



