180 oberholser: a new family of passeriformes 



The water determinations (Table 2) were made by heating 

 coarse powder in a covered platinum dish. The powder not used 

 was kept for three months in a small vial in a balance case in 

 which the air was dried with sulfuric acid, and was then found to 

 have lost spontaneously 5 per cent of water. Obviously, the 

 water in halloysite is in part only mechanically held. This part 

 is given off very readily, and the resulting partially dehydrated 

 material has a composition near that of kaolinite. The formula 

 should therefore probably be written Al2O3.2SiO2.2H2O.Aq. 



The effects of the loss of water on the optical properties are 

 shown in Table 3. 



The close approach of this and many other analyses of halloy- 

 site to the composition Al 2 3 .2Si02.2H 2 O.Aq, combined with the 

 results of optical examination given above, indicates that the 

 material called halloysite is the amorphous mineral correspond- 

 ing to crystalline kaolinite, holding through capillarity or adsorp- 

 tion more or less excess water. 



ORNITHOLOGY. — Diagnosis of a new laniine family of Passeri- 

 formes. Harry C. Oberholser, Bureau of Biological Sur- 

 vey. 



The peculiar shrike-like Madagascar genus Tylas has commonly 

 been considered a member of the family Pycnonotidae. This 

 disposition has probably been due to its nuchal hairs, and to the 

 character of its external nares, which in general resemble those 

 of the genus Otocompsa. 



As Mr. W. P. Pycraft has recently shown, 1 this genus is really 

 not closely allied to the Pycnonotidae. Neither is it a member 

 of the Prionopidae, to which family Mr. Pycraft has proposed to 

 refer it, apparently for want of a more satisfactory place. While 

 in some osteological respects it resembles the Prionopidae, it has 

 also resemblances to the Muscicapidae, and, on the whole, pre- 

 sents a very curious combination of characters, a condition re- 

 flected in the difficulty authors have had in referring it to the 

 proper family. 



That it does not belong in the Prionopidae is at once evident 



1 Proc. Zool. Soc. Lond., 1907, p. 376. 



