| A | B |
|---|
| mammalia | mammals; high metabolic activity, presence of hair, presence of nipples |
| mamary glands | nipples (females have to feed young) |
| rodentia | order that rats and mice belong to |
| head, neck, trunk, tail | four general regions of rat |
| nictating membrane | third eyelid |
| auricle/pinna | external earflap |
| external acoustic meatus | ear canal |
| tympanic membrane | out of sight at base of meatus |
| vibrissae | whiskers |
| cranial part | section of trunk |
| thorax | ribs, heart, lung area |
| abdomen | liver, stomach, intestines |
| anus | male "termination of the digestive tract" |
| scrotum | two large sacs that contain testes |
| preputial oriface | protruding part that has prepuce and penis |
| prepuce | foreskin that surrounds penis |
| urinary aparture | female "termination of digestive tract" |
| mammary papillae | nipples |
| horny scales | found at base of tail |
| horny foot pad | found on feet |
| claw | found on most toes (except thumb) |
| pelvic appendage | hind limb |
| pectoral appendage | forelimb |
| clitoris | penis-like protruberance |
| vulva | depression where opening of vagina lies |
