18/3.] CAROTID ARTERIES OF BIRDS. 465 



CuCULID^E. 



Both carotids are present in these birds. 

 Species examined. 

 Cuculus canorus. Centropus senegalensis. 



Cacomantis sepulcralis. Guira piririgua. 



Chrysococcyx, sp. Phoenicophaes, sp. 



Ramphastid^e. 



The left carotid only is developed in these birds. 



Species examined. 

 Ramphastos cuvieri. Ramphastos carinatus. 



ariel. 



Capitonid-e. 



The left carotid only is present in these birds. 

 Species examined. 

 Megalcema asiatica. Indicator major. 



Barbatula duchaillui. 



PSITTACI. 



The Parrots are peculiar for the variation that occurs in their caro- 

 tids, which show four different arrangements : first, there may be two 

 in the normal position ; secondly, the right may, as it usually does, 

 traverse the hypapophysial canal, whilst the left, in a manner quite 

 exceptional, runs superficially along the side of the neck in company 

 with the left pneumogastric nerve and the left jugular vein ; thirdly, 

 the right may be very small, and blend with the much larger normally 

 situated left (in Cacatua sulphurea, according to Meckel) ; and, 

 fourthly, the left may alone be developed, as in the Passeres. The 

 first of these four conditions is only found in Old- World Parrots"; 

 and the last two are restricted to the Cacatuiose. 



Species examined. 

 In the following species the first plan prevails, the two carotids 

 running normally : — 



Stringops habroptilus. Prioniturus, sp. 



Calopsitta novce-hollandice. Lorius cardinalis. 



Eolophus(Cacatua) roseicapillus. Eos indica. 

 Euphema pulchella. Trichoglossus concinnus. 



splendida. Loriculus, sp. 



bourkii. Aprosmictus scapulatus. 



Melopsittacus undulatus. Palceornis alexandri. 



Agapornis roseicollis. 



The following species belong to the second division, the right carotid 

 running normally, whilst the left runs up the side of the neck, to- 

 gether with the left pneumogastric nerve and jugular vein : — 



Ara macao. Conarus xantholcemtis. 



Conurus cruentatus. jendaya. 



Proc. Zool. Soc— 1873, No. XXX. 30 



