the Family of Cuculidce. 221 



lies are united, so as to form a circle ; or, in other words, to point 

 out their internal affinities among themselves. I shall then slight- 

 ly notice their external affinities, or those relations by which they 

 are united to the conterminous families of the Scansores, that is, to 

 the Cerihiadce on one side, and to the Ramphasiidce on the other. 



First, as to their internal affinities. The progression from the 

 Cuculinae to the Coccyzince, or from the parasitic to the building 

 cuckoos, is so gradual, that our only difficulty is to discover the 

 precise point of their junction, or, in other words, which is the scan- 

 sorial type of each, for by these are all circles invariably united. 

 One of these appears to be the Cuculus Erythropthalmus of authors. 

 From the genus Coccyzus of M. Vieillot, the natural series passes 

 into Croiophaga, by means of the Cuculus guira of Linnaeus, rank- 

 ed by some as a Coccyzus, and by others as a Crotophaga. By this 

 genus, (the fissirostral type,) we leave the Coccyzi?ice and enter the 

 aberrant circle by means of the singular bird we shall subsequently 

 describe, and which at the same time opens a passage to Pheenico- 

 phaus : then follows Leptosomus and Saurothera, two remarkable 

 genera, which all writers have kept together. After these, I am dis- 

 posed to place the genus Opisthocomus, yet with a mark of doubt, 

 not having at this time the opportunity of minutely examining cer- 

 tain parts of its structure. Whether or no the Coccyzus Geoff royi of 

 the PL Col. pi. 7> and the Cocc. Delalandi of the same work, PL 

 440, two birds nearly as remote from the type of the family as is 

 Opisthocomus, really belong to this particular group, remains for fu- 

 ture investigation. The last division is only represented by a single 

 genus. This is composed of the well-known honey-guides of Africa : 

 fortunately, however, the affinity between this and the genus Eudy- 

 namys is sufficiently apparent to leave us in no doubt that they fol- 

 low each other, and by this affinity we once more return to the. ty- 

 pical genus Cuculus, and close the circle. 



The external affinities of the family will be found to strengthen 

 what has now been said on its internal relations. The Cuculidce, as 

 being the most aberrant form of the Scansores, is consequently that 

 by which the order Insessores is united to the Rasores, — the two 

 other aberrant divisions, as before remarked, leading to the Ram- 

 phastidce or toucans on one side, and to the Certhiadce or creepers 

 on the other. When we ri nd the Saurothera;, therefore, with large, 

 serrated, and hollow bills, we see at once the mode in which na- 

 ture has united the structure of a cuckoo with that of a toucan, 

 while, on looking to the honey-guides, we detect indications of that 

 rigidity in the tail-feathers, about to be fully developed among the 



