MAKVi.AM) c;i:uj.t)uic.vi, SI i;\i;v I!.") 



dens, likewise t'diiiiiliMl on imii|iir dciitiil i)lati'S rroin tlic l-lticfiic ami 

 !Miocriie ri'spcclivfly oT Nrw .Icim'V. \n \)v the first indications of tliis 

 n-cnus in North America. Neither .if tlie hist two species iiave l)ecn 

 fimii'cil, hill it is pidhal)h' from Marsirs hiief (h'sci'ipt ion tliat /'. rl('<i(iiis 

 is a voun^- examph' of /'. (oliapiciis. I'lirtherniore, it is practically cer- 

 tain that neither of Wvman's siKMimeiis are refcrahle to /-". toJidpinis, 

 but each is I'epreseiital i\(' t)f a distim-t species. Whethi'r their horizon 

 is Kocene or .Miocene was not eoiiclii>i\ cly (h'termiiied hy Wyiiian. 

 althoimli the ehani'es are in fa\or of att rihiit in,i:- tiiein to the former. 

 'J^races of tliis genus liaxc not as yet heen discovered in ]\Iaryland, ])ut 

 the folhnving species deserves notice on account of its historical and 

 seientilic interest. 



PlIYLLODUS IIUM'ARIOXYX U. Sp. 



riiijlloihix sp. all'. ioUapkns Wyman, 18.50, Anier. Jour. Sci., ser. ii, vol. x, p. 234, 

 woodc. fill.'. '.'(^ 



Type. — Detached, dental plate; formerly in Museum of Comparative 

 Zoology, Cambridge, Mass. 



OTOLITES. 

 Plate XII, Figs. 4-6. 

 Fish otolites, or '" ear-stones,"" are found almost exclusively in the 

 detached condition, this being due to the fact that they are held in 

 place during life only by membranes, and hence readily fall out from 

 the head and sink to the bottom while the decomposing body of the fish 

 continues to float on the surface, a prey to all sorts of creatures, or is 

 cast ashore by the waves. The circumstance of large numbers of fossil 

 fish skeletons being found in close proximity to one another, bnt none 

 of them having otolites preserved in situ, is cited as an argument against 

 their having met their death suddenly or in slioals. The peculiar struc- 

 ture and composition of otolites favor their preservation in the fossil 

 state, hence it is not surprising that they should occur in considerable 

 abundance and variety throughout the Tertiary and even older horizons. 

 Eather is it the converse proposition which excites wonder; for when we 

 consider the number of forms represented solely by ear-bones, it is diffi- 

 cult to understand why not a vestige of other parts of the skeleton re- 

 mains. 

 s 



