MARCH 4, 1921 abstracts: inorganic chemistry 111 



INORGANIC CHElSIIvSTRY.— r/?r binary system dkermanite-gchlcniie. 

 J.,B. Ferguson and A. F. Buddington. Amer. Journ. vSci. IV. 50: 

 131-140. 1920. 

 The binary system akemianite (2CaO.Mg0.2Si02)-gehlenite (2CaO.- 

 AljO.-i.SiOo) was studied by the quencjiing method and the solidus and liq- 

 uidus curves determined. The system forms a complete series of solid solu- 

 tions with a minimum melting point about 70° below the melting point of 

 akermanite, the component of lower melting point, at a composition of about 

 74 per cent akermanite and 26 per cent gehlenite. Akermanite was found 

 to show the unusual feature of its glas having a greater density than the 

 corresponding crystals at 25° C. The optical characters of the crystals 

 are a continuous function of the composition. Akermanite is positive in 

 its optical characters and gehlenite is negative. Crystals of certain inter- 

 mediate compositions are isotropic for light of a definite wave length and 

 constitute a transition phase between positive and negative crystals. 



A. F. B. 



ORNITHOLOGY. — Some notes on the plumage of the male Florida Red- 

 wing {Agelaius p. fioridanits) . F. C. Lincoln. Proc. Biol. Soc. Wash. 

 32: 196-197. 1919. 

 A considerable number of non-breeding males of Agelaius phoeniceus 

 floridanns were found in Louisiana in June. These birds, though at least 

 a year old, showed clear evidence of immaturity on their obscured or dull- 

 colored orange shoulder patches, and in many cases also in the much less 

 brilliant color of other parts of the plumage, particularly of the black 

 body areas. It would be interesting to know w^hether this condition is 

 common to all the subspecies of Agelaius phoeniceus. 



Harry C. Oberholser. 



ORNITHOLOGY. — The relationships and geographical distribution of the species 

 and races belonging to the genus Rhynchocyclus. Charles B. Cory. 

 Proc. Biol. Soc. Wash. 32: 217-224. 1919. 

 A synoptical revision of the tyrannine genus Rhynchocyclus results in 

 the recognition of twenty forms, all of which have been hitherto described. 

 Of Rhynchocyclus sulphurescens , six forms prove to be valid; of Rhyncho- 

 cyclus cinereiceps, two; of Rhynchocyclus peruvianus, two; of Rhynchocyclus 

 marginatus, two: of Rhynchocyclus megacephalus, one; of Rhynchocyclus 

 poliocephalus, three; oi Rhynchocyclus grisescens, one; and oi Rhynchocyclus 

 flaviventris, three. Comparison also shows that Rhynchocyclus sulphurescens 

 pallescens Hartert and Goodson is a synonym, of Rhynchocyclus sidphurescens 

 (Spix); and Rhynchocyclus sidphurescens asemus Bangs is a subspecies of 

 Rhynchocyclus cinereiceps rather than of Rhynchocyclus sulphurescens. 



Harry C. Oberholser. 



ORNITHOLOGY. — Descriptions of proposed new birds from Peru, Bolivia, 



Brazil, and Colombia. Frank M. Chapman. Proc. Biol. Soc. Wash. 



32: 2.53-268. 1919. 



Further study of collections of birds from South American has resulted 



in the discovery of a number of birds new to science. Among these is a 



new genus of Furnariidae most closely allied to Automolus and here named 



Hylocryptus. The following new species and subspecies are also described: 



