A. Smith Woodward — Visit to American Museum's. 391 



being rapidly augmented, and all the more important of the latest 

 acquisitions are described in Dr. Newberry's new volume just issued 

 by the U. S. Geological Survey. 



The bones of Dinichthys and its allied genera usually occur in a 

 black shaly matrix, from which they can be completely extricated ; 

 and they are often associated in natural groups, the plates of a single 

 individual being met with together, though difficult to disinter intact 

 on account of their huge dimensions. To one accustomed to the 

 skeleton of the common Coccostevs, the remains of the American fish 

 appear as magnified representatives of familiar bones; and other 

 equally gigantic modifications of the same type have lately been 

 named Trachostens and Titanichlhys. 



Next to the Placoderm Fishes, the most striking of recent acqui- 

 sitions are nearly complete examples of one of the Carboniferous 

 sharks whose teeth have long been known under the name of Clado- 

 dus. Though showing some remarkable features, — such as a ring 

 of circumorbital plates, abbreviate pectoral fins, and a diphy cereal 

 tail with a pair of great horizontal expansions of integument at its 

 base, — the fish invariably rests upon its back (having been round- 

 bodied), and thus gives no clue to one interesting character, i.e. the 

 presence or absence of dorsal fin-spines. Among other unique t}'pes 

 is the Devonian Oitychodus, with the strange coil of spike-like teeth 

 undoubtedly fixed in front of its lower jaw ; and all the bones of 

 this fish are so remarkably scattered that it is still difficult to form 

 any conclusion as to its affinities. Numerous jaws of Devonian 

 Chimseroids, the spines of Machcer acanthus , and various remains of 

 small Placoderms are also almost unique; and among the Carbon- 

 iferous Limestone fossils are numerous types of Selachian spines 

 and teeth. Of the latter, the great teeth named Archceobatis are 

 perhaps most conspicuous ; and these, it will be observed, differ in 

 no respects from the British teeth assigned to Psammodus, except 

 in the coarser nature of their coronal ornament. A large series of 

 Coelacanth, Pala3oniscid, and other fishes, with several Amphibia, 

 from the Coal-measures of Ohio, forms the type collection described 

 by Profs. Newberry and Cope in the Reports of the Geological Survey 

 of Ohio. Still higher in the geological scale, another fine collection 

 of fishes illustrates the American Trias ; and this, again, has been 

 made available for reference by the Professor's well-illustrated 

 volume published by the U. S. Geol. Survey in 1888. Many of 

 these specimens were obtained from an excavation specially made 

 at Boonton, New Jersey, which not only enriched the Museum with 

 material, but added greatly to previous knowledge of the fish-fauna 

 in question. 



The American Museum of Natural History, in the Central Park, 

 though as yet insignificant when compared with the plan for its 

 completion, already comprises fine, lofty exhibition galleries and 

 work-rooms, and, in addition, is provided with the largest and most 

 completely fitted lecture theatre that has hitherto been built in 

 conjunction with an institution of this kind. Each spring and 

 autumn, the theatre is occupied by Prof. Bickmore, who delivers 



