PASSEEES 173 



at all, lying loosely over the liver, or have but one attach- 

 ment, which they share with the falciform ligament. 



It is very general — but there are a few exceptions, which 

 will be dealt with later — for the sternum to have a forked 

 manubrium in front and a single pair of notches behind.. 



The number of rectrices present among passerine birds 

 varies. They are, indeed, completely absent in wrens of the 

 genus Pnoepyga. Twelve is the usual number, but ten only 

 occur in Xenicus, Phrenotrix, and Edolius, while Menura 

 superbahas sixteen. The aftershaft is ' very weak and downy ' 

 when present, and is sometimes (e.g. Paradisea rubra) absent 

 altogether. As to the pterylosis, we may take Ampelis 

 cedrorum, recently described by Shxjfbldt,i as an example 

 of passerine pterylosis, mentioning afterwards such varia- 

 tions from this type as are met with. In the bird in question 

 the dorsal tract is exceedingly narrow from the origin in the 

 fairly continuous feathering of the head down to a point in 

 the pelvic region, where it is greatly dilated to form a 

 diamond-shaped area ; this again contracts to the original 

 dimensions, and the tract concludes a little way in front of 

 the base of the oil gland. From the lateral angles of the 

 diamond-shaped area a tract runs to the feathering of the 

 legs. On either side of the oil gland arises a short tract, 

 which does not leave the trunk, but appears to be the hinder 

 part of the femoral tract of some other birds. It is perhaps 

 noteworthy that it is very similar to the corresponding one 

 of the Bucconidae and Capitonidse, also, however, of the 

 kingfishers. 



The ventral tract divides early on the neck, and on the 

 breast is increased in breadth, the outer rows of feathers 

 being much stronger than the inner set ; the latter (not the 

 former) are continued down to the cloacal orifice, which 

 they completely surround by a narrowish band of feathers. 

 The humeral tracts, which are strong, are connected with 

 the head feathering by a special neck band as wide as the 

 dorsal tract. Nitzsch does not figure this connection or 

 that of the diamond-shaped dorsal area of feathers with the 



' In a paper dealing with Macroohires in /. Lnn. Soc. vol. xx. 



