SINGULAR.
Nom.  senex           caro            os
Gen.  senis           carnis          ossis
Dat.  seni            carni           ossi
Acc.  senem           carnem          os
Voc.  senex           caro            os
Abl.  sene            carne           osse

PLURAL.
Nom.  senes           carnes          ossa
Gen.  senum           carnium         ossium
Dat.  senibus         carnibus        ossibus
Acc.  senes           carnes          ossa
Voc.  senes           carnes          ossa
Abl.  senibus         carnibus        ossibus

1.  Iter, itineris, n., way, is inflected regularly throughout from the stem itiner-.

2.  Supellex, supellectilis, f., furniture, is confined to the Singular.  The oblique cases are formed from the stem supellectil-.  The ablative has both -i and -e.

3.  Jecur, n., liver, forms its oblique cases from two stems,—­jecor- and jecinor-.  Thus, Gen. jecoris or jecinoris.

4.  Femur, n., thigh, usually forms its oblique cases from the stem femor-, but sometimes from the stem femin-.  Thus, Gen. femoris or feminis.

General Principles of Gender in the Third Declension.

43. 1.  Nouns in -o, -or, -os, -er, -es are Masculine.

2.  Nouns in -as, -es, -is, -ys, -x, -s (preceded by a consonant); -do, -go (Genitive -inis); -io (abstract and collective), -us (Genitive -atis or -udis) are Feminine.

3.  Nouns ending in -a, -e, -i, -y, -o, -l, -n, -t, -ar, -ur, -us are Neuter.

Chief Exceptions to Gender in the Third Declension.

44.  Exceptions to the Rule for Masculines.

1.  Nouns in -o.

  a.  Feminine:  caro, flesh.

2.  Nouns in -or.

  a.  Feminine:  arbor, tree.

  b.  Neuter:  aequor, sea; cor, heart; marmor, marble.

3.  Nouns in -os.

  a.  Feminine:  dos, dowry.

  b.  Neuter:  os (oris), mouth.

4.  Nouns in -er.

  a.  Feminine:  linter, skiff.

  b.  Neuter:  cadaver, corpse; iter, way; tuber, tumor; uber, udder. 
  Also botanical names in -er; as, acer, maple.

5.  Nouns in -es.

  a.  Feminine:  seges, crop.

45.  Exceptions to the Rule for Feminines.

1.  Nouns in -as.

  a.  Masculine:  vas, bondsman.

  b.  Neuter:  vas, vessel.

2.  Nouns in -es.

  a.  Masculine:  aries, ram; paries, wall; pes, foot.

3.  Nouns in -is.

  a.  Masculine:  all nouns in -nis and -guis; as, amnis, river; ignis,
  fire; panis, bread; sanguis, blood; unguis, nail.

  Also—­

axis, axle. piscis, fish. collis, hill. postis, post. fascis, bundle. pulvis, dust. lapis, stone. orbis, circle. mensis, month. sentis, brier.

4.  Nouns in -x.