December 12, 1902.] 



SCIENCE. 



953 



ahow specific differences in some of them, but 

 the resemblance in any event is marvelous. 



The Converse County collections of which 

 I have spoken include more or less numerous 

 representatives of Chamops, Iguanavus, Coni- 

 ophis and Cimolopteryx, originally described 

 by Marsh from these regions, together veith 

 others that are yet new, and the following 

 which have been recorded from other deposits 

 only : 



Myledaphus hipartitus Cope. — This species, 

 originally described from the Montana beds, 

 is common in the Wyoming deposits. The 

 teeth are variable in size, and seem to agree 

 well with that figured by Lambe from the 

 Belly River deposits by Lambe. It is of in- 

 terest to add that the genus is closely allied 

 to, possibly identical with, Bhomhodus Dames, 

 from the uppermost Cretaceous of Europe. 

 Jaekel shows clearly that Bhomhodus belongs 

 among the Trygonidse. 



Accipenser alhertensis Lambe. — The keeled 

 and ornamented shield figured by Lambe from 

 the Belly River appears to be identical with 

 others in the Baur collection from Wyoming. 

 I suspect that they belong with a fish difi'erent 

 f vom Accipenser. 



Lepidosteus occidenialis Leidy. — Numerous 

 scutes, associated with opisthocoelous verte- 

 brffi, from Converse County can not be dis- 

 tinguished from this species, originally de- 

 scribed from the Judith River and recognized 

 by Lambe from the Belly River. 



Crocodilus Jmmilis Leidy. — This species 

 was described from the Judith River beds, 

 and is identified by Lambe from the Belly 

 River. Numerous teeth, scutes and vertebrse 

 from the Converse County beds can not be 

 distinguished. 



Scapherpeton tectum Cope. — The four 

 known species of this genus are typically 

 from the Judith River beds. Lambe has 

 identified the above species from the Belly 

 River. Numerous vertebrae and fragments of 

 the mandible are in the W.yoming collections, . 

 among which I recognize this species. 



Champsosaurus. — This genus is well repre- 

 sented in the Laramie collections. 



Aublysodon {Deinodon, preoe.). — Teeth of 

 carnivorous dinosaurs are not at all rare in 



the Converse beds, some of which agree well 

 with the figure of A. explanatus Cope given 

 by Lambe. 



Paleoscincus. — Teeth of three or four 

 species from the Wyoming deposits are re- 

 ferred to this genus (evidently a composite 

 one) among which there is one that seems 

 identical with P. asper, described by Lambe 

 from the Belly River. 



Baena is well represented in the collections, 

 doubtless including B. Hatcheri among 

 them, which is also known from the Belly 

 River. 



S. W. WiLLISTON. 



University of Chicago, 

 November 24, 1902. 



BOTANICAL NOTES. 



AIR HUMIDITY. 



Studies made on the hmnidity of the air 

 in an ofiice in Lincoln, Nebr., by G. A. Love- 

 land, and reported to the Nebraska Academy 

 of Sciences, January, 1902, show that the air 

 is much drier in the winter than is commonly 

 supposed. Thus in an ofiice in Nebraska 

 Hall on the campus of the University of 

 Nebraska the following results were obtained 

 for the winter of 1899-1900. 



Mean Exterior Mean Relative 



Temperature. Humidity. 



December 22.6° 18.6 per cent. 



January 26.8° 21.0 " " 



February 19.2° 15.3 " " 



The ofiice in which these observations were 

 made is on the main floor of a large brick 

 building which is heated by steam, using 

 ordinary pipe radiators. On the same floor 

 a few feet away are the rooms of the Botan- 

 ical Department, one of which is used for 

 physiological experiments. It will be seen 

 very readily that experiments upon ordinary 

 plants must be made in such a dry air with 

 considerable difficulty, and these results may 

 help some students to understand why their 

 work has been unsatisfactory. The air in 

 such rooms is drier than in the driest climates 

 in the world, and the effect on plants under 

 observation can not be otherwise than most 

 trying. Plants for study are taken from the 



