THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



No. 86. JUNE 1844. 



XL VI. — Desa'iptions of several new or imperfectly-defined Genera 

 and Species of Birds. By H. E. Strickland, M.A. 



[With Four Plates.] 



The details of zoology are now diffused over so wide a field of 

 literature, that it is next to impossible to pronounce with cer- 

 tainty that any given specimen belongs to an undescribed spe- 

 cies j and although confusion is often caused by the too hasty 

 and careless definition under new names of species previously 

 described, yet, on the other hand, science may be retarded by too 

 great backwardness in making known new species and groups. 

 With this feeling I now venture to describe a few out of many 

 species of birds which have long remained unnamed in my cabi- 

 net ; and though it is very possible that some of them may be 

 already described in works to which I have not had access, yet 

 having searched carefully through a large number of ornitholo- 

 gical publications without meeting with any notice of these spe- 

 cies, I am disposed to believe tbat the majority of them are really 

 nondescript. 



FALCONID^, ACCIPITRINtE. 



Genus Ischnosceles, Strickland (Iff-xyoffKeXris, exilia habens crura). 



Rostrum asturinum, subexiguum, elevatum, compressum, cera 

 longiuscula, culmine satis curvato, dertro hamato, commissura sub- 

 recta, vix sinuata, dertrum versus subito deflexa, mandibula debili, 

 denticulo obtuso versus apicem instructa, gonyde vix ascendente. 

 Nares ovatse, obliquse. Alse mediocres, caudse trientem attingentes, 

 rotundatae, remigibus graduatis, 5*^ et 6^ longissimis. Cauda elon- 

 gata, rotundata. Tarsi gracillimi, acrotarsiis paratarsiisque scutatis, 

 scutis Isevigatis, subobsoletis. Digiti graciles, digitus medius elon- 

 gatus, externus interno multum brevior. Ungues curvati, acuti, sub- 

 tus complanati, externus longe minimus, alii subsequales. 



Typus Ischnosceles gracilis (Falco gracilis, Temm. PI. Col. 91). 



The slenderness of the tarsi in this bird, and the remarkable 

 proportions of the toes, seem to justify its generic separation 

 from Astur and from Accipiter, where it has been hitherto classed. 

 The external toe (exclusive of the claw) falls short of the extre- 



Ann. ^ Mag. N, Hist. Vol. xiii. 2 E 



