Happy New Year, Steven! :-)

Since you refer to toxicology reports being done with "rhesus macaques", it seems that "long-tailed macaque" would make a good counter name.

I found that "Old world monkeys" or Cercopithecidae are a family of primates whichs include baboons and macaques.

I found a macaque called a "long-tailed macaque" per below (it has many names according to Wikipedia including crab-eating monkey). It is used in lab experiments.

The common name of this animal varies. It is commonly referred to as the Long-tailed Macaque because the tail of this macaque is usually about the same length as its body and because its long tail distinguishes it from most other macaques. The species is also commonly known as the Crab-eating Macaque. Another common name for M. fascicularis is the Cynomolgous Monkey, which literally means "dog-milker" monkey, which is the name most commonly used for these animals in laboratory settings.

Guenon = any of several long-tailed African monkeys, esp. of the genus Cercopithecus, having a grizzled coat.

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Note added at 1 day13 hrs (2010-01-04 03:26:17 GMT)
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Guenon is the name of monkey (any of the long tailed Afrikan monkeys) that is used in lab experiments and belongs to the genus Cercopithecus.

Refer: http://en.wikipedia.org/wiki/Guenon

Classification:

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Cercopithecidae
Subfamily: Cercopithecinae
Tribe: Cercopithecini
Genus: Cercopithecus