श्लोकः
सङ्करो नरकायैव कुलघ्नानां कुलस्य च।
पतन्ति पितरो ह्येषां लुप्तपिण्डोदकक्रियाः।।१-४२।।

सन्धि विग्रहः
सङ्करः नरकाय एव कुल-घ्नानाम् कुलस्य च।
पतन्ति पितरः हि एषाम् लुप्त-पिण्ड-उदक-क्रियाः।।१-४२।।

श्लोकार्थः
सङ्करः कुल-घ्नानाम् कुलस्य च नरकाय एव (भवति);
हि एषाम् पितरः लुप्त-पिण्ड-उदक-क्रियाः  (सन्तः)  पतन्ति।

शब्दार्थः
1.42 सङ्करः=such unwanted children नरकाय=make for hellish life एव=certainly कुल-घ्नानाम्=for those who are killers of the family कुलस्य=for the family च=also पतन्ति=fall down पितरः=forefathers हि=certainlyएषाम्=of them लुप्त=stopped पिण्ड=of offerings of food उदक=and water क्रियाः=performances

Meaning
1.42: Commingling (of castes) brings hell to the family and those who destroyed the race. The spirits of the ancestors fall, deprived of their offerings of food and water.

Purport:
Because of commingling of castes, the family and the destroyers of the race go to hell. The spirit of the ancestor falls, deprived of the offerings of food and water.