tin singular._

(a) _Sing._ _Plur._ | (b) _Sing._ _Plur._
Apparatus apparat-us | Caries cari-es
Hiatus hiat-us | Congeries congeri-es
Impetus impet-us | Series seri-es
| Species speci-es
| Superficies superfici-es.

SECOND CLASS.

_Words wherein the Latin plural is formed from the Latin singular by
changing the last syllable._

(a).--_Where the singular termination -a is changed in the plural into
-ae_:--

_Sing._ _Plur._ | _Sing._ _Plur._
Formul-a formul-ae | Nebul-a nebul-ae
Lamin-a lamin-ae | Scori-a scori-ae.
Larv-a larv-ae |

(b).--_Where the singular termination -us is changed in the plural into
-i_:--

_Sing._ _Plur._ | _Sing._ _Plur._
Calcul-us calcul-i | Polyp-us polyp-i
Coloss-us coloss-i | Radi-us radi-i
Convolvul-us convolvul-i | Ranuncul-us ranuncul-i
Foc-us foc-i | Sarcophag-us sarcophag-i
Geni-us geni-i | Schirr-us schirrh-i
Mag-us mag-i | Stimul-us stimul-i
Nautil-us nautil-i | Tumul-us tumul-i.
Oesophag-us oesophag-i |

(c).--_Where the singular termination -um is changed in the plural into
-a_:--

_Sing._ _Plur._ | _Sing._ _Plur._
Animalcul-um animalcul-a | Mausole-um mausole-a
Arcan-um arcan-a | Medi-um medi-a
Collyri-um collyri-a | Memorand-um memorand-a
Dat-um dat-a | Menstru-um menstru-a
Desiderat-um desiderat-a | Moment-um moment-a
Effluvi-um effluvi-a | Premi-um premi-a
Empori-um empori-a | Scholi-um scholi-a
Encomi-um encomi-a | Spectr-um spectr-a
Errat-um errat-a | Specul-um specul-a
Gymnasi-um gymnasi-a | Strat-um strat-a
Lixivi-um lixivi-a | Succedane-um succedane-a.
Lustr-um lustr-a |

(d).--_Where the singular termination -is is changed