148 Proceedings of the Royal Society of Victoria. 



also occurs at their distal ends. For the most part they are 

 shown merely as grooves in the matrix, but in one instance a 

 hollow cylinder of bone is preserved, showing them to have been 

 fairly well ossified. The baseosts are also ossified, but their 

 relation to the axonosts cannot be clearly made out, owing to the 

 presence of matrix. The supports of the anal, whether axonosts 

 or baseosts is, from the nature of the specimen, uncertain, are also 

 covered with a layer of bone. 



The rays of all the fins are jointed, and as shown in the axial 

 line of the tail are branched repeatedly. This branching is not 

 seen elsewhere in the tail, so that very little of the caudal seems 

 missing in the mid line, or in other words the tail is deeply cleft. 

 At first sight the neural spines in the caudal region appear to have 

 the supports of the fulcral scales of the upper edge of the caudal 

 fitted directly on to them, but a thin raised line of ferruginous 

 material cutting across most of them at the same level may 

 perhaps mark a division of the bones, and indicate that the fulcral 

 scales rest not directly on the neural spines, but on a moi'e distal 

 series. There are no scales on the body except on the upper 

 caudal lobe where they are lozenge-sliaped on the upperside, and 

 oat-shaped on the lower. Their substance is thick and externally 

 they are doubtfully smooth or very finely longitudinally grooved. 

 The upper border of the caudal is furnished with a single row of 

 large fulcral scales. Smaller fulcral scales are also indicated in 

 front of the dorsal. As the front margins of the other fins are 

 absent, their presence elsewhere is uncertain. 



Length from posterior end (broken) of the notochord to the 

 anterior edge of the origin of the dorsal is about 260 mm. 

 Dorso- ventral diameter of the pedicel of the tail about 45 mm., 

 and of the body at the middle of the dorsal fin 70 or 80 mva. 

 The lozenge-shaped scales on the tail measure 5 by 2*5 mm., and 

 the oat-shaped scales 11 by 3 mm. 



The specific name is a tribute to Dr. A. R. 0. Selwyn, who 

 first geologically examined the district whence the specimen 

 came. 



Locality. — Carrapook (Muntham), county of Dundas, Western 

 Victoria. From a tank sunk by Mr. Stock at his house, and 

 forwarded by Mr. J. S. McPherson. 



