TROGLODYTID^. 93 



the roof of the cavity to its upper anterior extremity, constantly 

 diminishing in depth (as in Thryophilua), or is carried still further 

 round to the lower anterior end, as in Salpinctes, where it is arched 

 outwards so as to be parallel with the external scale. This septum 

 is not noticeable iu the specimen of Heleodtjles before me ; in all 

 others where the nostrils are sufficiently open it is quite appreciable. 

 This lateral septum is sometimes vertical or parallel to the median 

 septum ; in Ginnicerthia, however, it is slightly revolute, showing a 

 free edge perpendicular to the median plane, which forms a low wall 

 dividing the oval nasal cavity into two parts, but not coming to the 

 surface. In Heterorhina this wall is higher, reaching the level of 

 the nostrils, but not adherent to the edges; while in Microcer cuius, 

 if the indications of the poor specimens of M. hamhla before me are 

 not misinterpreted, this septum is united to the edges, forming a 

 bridge separating two cavities. 



In most forms of Troglodylidse the nostrils occupy the lower side 

 of the nasal groove, and are more or less elongated, and overhung 

 by a valvular convex or vaulted projection of the nasal membrane, 

 which is thickened and rounded at the edges. This varies in de- 

 velopment, least in Campylorhynchus, more distinct in TJiryoihorus ; 

 while in Pheugopedius, it seems almost to close the aperture. In 

 Thryophilus, however, this scale-like projection appears to be 

 entirely wanting, leaving the nasal cavity broadly open, and the 

 lateral cavity much exposed. In Heleodytes, and in some forms of 

 Campylorhynchus, the nasal aperture, as in Donacohius, has its 

 anterior half resting in the end of the nasal groove, bordered only 

 behind and by thin membrane only, and with no lateral septum visi- 

 ble. In Cyphorinus, the nostril is small, circular, and entirely sur- 

 rounded by membrane. In the others, it rests against the lower 

 side of the nasal groove at its anterior extremity, with membrane 

 above and behind it only. 



The bill, in most species, is long, slender, subulate, and decurved ; 

 in Ginnicerthia, it is more conical. It is generally without notch 

 at the end, except in Cyphorinus, Microcer cuius, Heterorhina, and 

 TJiryophilus. The feathers of the forehead do not come as far for- 

 ward as the nostrils, as a general rule. 



The lateral toes are about equal, the outer very little the longer ; 

 in Salpinctes and Catherpes, however, the discrepancy is very 

 marked. In Heleodytes the tarsus is as short as the middle toe, or 

 shorter ; in all others it is longer, generally considerably so. The 

 legs are very stout in Heleodytes, Campylorhynchus, and Ginnicer- 

 thia ; in the others they are more slender. 



