530 A. Smith Woochcard — The Cretaceous Saw-Fish. 



by which the rostrum and trunk are proved to pertain to one and 

 the same fish. The specimens are three in number, all in the British 

 Museum, and may be enumerated as follows : — 



(1) No. 53663. A much crushed rostrum, showing part of the 

 mouth at its base, having teeth identical with those of the type- 

 specimen of Squatina crassidens, and also one complete propterygial 

 cartilage of the pectoral fin identical with that of the same type- 

 specimen. 



(2) No. 49518. Imperfect abdominal region identical with that of 

 Squatina crassidens, showing patches of large, strongly calcified 

 tesseras, exactly resembling those of the rostral cartilages of Sclero- 

 rhijnclms, and unknown in any other Lebanon fish. 



(3) No. 49547. Middle portion of fish, undoubtedly Sq. crassidens, 

 displaying teeth and pectoral propterygium identical with those of 

 No. 53663, and showing a detached patch of the characteristic rostral 

 cartilage. 



The general form and proportions of the trunk in the restoration 

 are based upon the type-specimen of Squatina crassidens ; while the 

 proportions of the rostrum are inferred from the type-specimen of 

 Sclerorhynchus ataviis, and the tip of a small rostrum of a similar 

 kind in the Paris Museum of Natural History.^ Some details are 

 added from other imperfect fossils noticed in the British Museum 

 Catalogue. 



Description. 



Head. — The rostrum seems to have occupied not less than one- 

 third of the total length of the fish, and its length equals about five 

 times its maximum width at the base. If the Paris specimen be 

 correctly interpreted as the extremity of the snout, the median 

 rostral cartilage is shown to extend throughout its length ; and the 

 pair of broad lateral cartilages, fixed at the base between the anterior 

 part of the nasal capsules and the narrow median cartilage, soon 

 begins to occupy the whole of the space between this cartilage and 

 the toothed margin of the blade on each side. The integument 

 extends up the base of the rostrum in such a manner that there is 

 no sharp line of demarcation between the head and the " saw " ; 

 while a gradual passage can even be observed between the ordinary 

 dermal tubercles of the body and the elongated teeth arranged in 

 a single regular series on each lateral rostral border. None of these 

 teeth are fixed in sockets of the cartilage ; but each comprises a 

 high, round, crimped base, fixed in the skin in the usual manner, 

 with a long, enamelled, exserted portion, compressed to an anterior 

 and posterior acute edge. On the anterior ])order of each nasal 

 capsule there is a sharply-defined, well-calcified triangular exten- 

 sion, apparently to be regarded as an abbreviate prepalatine cartilage; 

 and amid the indecipherable remains of the cranium behind, the 

 form and proportions of the jaws are distinguishable, as given in 

 the figure. Several series of teeth seem to have been simultaneously 

 functional in the jaws, and they are uniform in charactei'. Each 



1 Proc. Zool. Soc. 1889, p. 450, woodcut. 



