ON THE ANATOMY OF THE PARROTS. 249 
the side of the neck in company with the left pneumogastric nerve and 
the jugular vein; or the left carotid may alone be developed, as in the 
Passeres and many other birds. It has been stated that Meckel found 
_@ fourth arrangement in Cacatua sulphurea; but in a specimen of 
that species recently dissected by me, the left only was present, as in 
C. cristata, C. leadbeateri, and C. galerita. 
To make this paper complete in itself, and to incorporate those 
dissections performed since the other was published, a list of all the 
Parrots which I have examined, together with the condition observed 
in them is given. 
1. I eecclidirdae peceentt, rasinitgy niosmallf, eidd BY side, im 
Agapornis, Loriculus, 
Aprosmictus, Lorius, 
Calopsitta, Melopsitiacus, 
Calyptorhynchus, Paleornis, 
Eeclectus, Prioniturus, 
Eolophus, Psittinus, 
Eos, Stringops, 
Euphema, Tanygnathus, 
Geopsittacus, Trichoglossus. 
Liemetis, 
é 2. The left carotid only is present in 
Cacatua. 
3. The two carotids are present, the right having its normal 
_ course, the left running superficially along with the left pneumogastric 
nerve in 
Ara, Nestor, 
Bolborhynchus, Pionus, 
Brotogerys, Platycercus, 
Caica, Peocephalus, 
Chrysotis, | —- Psephotus, 
Conurus, Psitiacus, 
Coracopsts, Psittacula, 
Cyanorhamphus, _ Pyrrhulopsis, 
Lathamus, Pyrrhura. 
Page 589. 
It may be observed that the only other well-defined groups of birds 
in which the carotids vary are the Cypselide, Gallinz, Struthiones, 
and Otidex. 
~ 
Il. The presence or absence of the ambiens muscle. 
The ambiens muscle, the tendon of which crosses the front of the 
knee-capsule obliqnely from above downwards and outwards, and ulti- 
Taal 
. 
fe 
