Final answer:
Haplorrhine primates lack a tapetum lucidum, a reflective layer in the eye that enhances night vision, which strepsirrhine primates possess.
Step-by-step explanation:
Unlike strepsirrhine primates, haplorrhine primates lack a tapetum lucidum. The tapetum lucidum is a reflective layer behind the retina that enhances night vision. It's important to note that haplorrhines include tarsiers, simians such as New World monkeys, Old World monkeys, apes, and humans. These primates tend to be diurnal and rely more heavily on vision rather than smell, hence the absence of the tapetum lucidum. All primates, including haplorrhines, possess tails, premolars, and fingernails as part of their anatomy, therefore these features are not what haplorrhines lack when compared to strepsirrhines.