Art. XVI. — A New Genus and a New Species of Fish 

 from the Mesozoic Rocks of Victoria. 



By T. S. hall, M.A., 



Demonstrator and Assistant Lecturer in Biology in the University of 



Melbourne. 



(With Plate XIV.) 



[Read 16th November, 1899]. 



The fish dealt with in this communication have been in my 

 hands for some time, and as no fresh material which would shed 

 additional light on their structure is available, I have thought 

 it better to treat what I have, rather than let the interesting 

 fact of the presence of fish in our mesozoic rocks remain longer 

 unrecorded. 



Psilichthys, gen. nov. 



Body long, slender. Scales absent except on the upper caudal 

 lobe, where they are thick and rhomboidal. Caudal forked. 

 Dorsal partly over anal and partly over the space between the 

 anal and the ventrals. Fulcral scales large and thick ; present 

 on both dorsal and caudal. The name refers to the absence of 

 scales on the body generally, 



Psilichthys selwyni, sp. nov. 



The posterior end only of the fish has been preserved, and 

 shows the tail, part of the anal fin and the origin of the dorsal. 



The body is narrow and elongate, the notochord is persistent, 

 and its sheath is not ossified. The neural arches and spines are 

 well developed, and towards the posterior end of the body are 

 inclined at a very low angle to the notochord. The haemal 

 arches and spines are similar to the neural, but the anterior ones 

 are forked at their inner ends. Ribs are absent. The axonosts 

 of the dorsal fin are twice as numerous as the obliquely inclined 

 neural spines, which they do not seem to meet, and they are 

 broadened or, in a few cases, forked at their inner ends. Forking 



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