Is “Behalves” A Proper Plural of “Behalf”?

The following sentence appears in a syllabus of a decision of the United States Court of Appeals for the 9th Circuit (at page 3):

The panel affirmed the district court’s dismissal of Longoria’s
family-members’ § 1983 claims. The panel held that only Longoria’s
estate could bring a § 1983 for the violation of his Fourth Amendment
rights; his family members had no standing to sue on their own
behalves.

My question relates to the correctness of the word in bold faced type in that sentence. I would have written that sentence: ” . . . ; no family member of Longoria had standing to sue on his or her behalf.” And, I have never seen the word “behalves” used in writing as a plural of “behalf.”

Is “behalves” a recognized plural of behalf in a context like the sentence quoted above?

Answer

Behalves was historically used as the plural of behalf. It is sometimes also spelled behalfs. While it is not commonly used today, you can occasionally still find the rare usage here and there.

Here is the entry on wiktionary

But if you look at the ngram viewer graph, you can see both versions had a sporadic usage and were never truly that popular.

Here are a few usages of the word in print.

…but now wee sue in your Lordshipps behalves… (1662)

…rather than that they should occasion a fruitless and calamitous
confusion in their behalfs. (1689)

…I’ll bring you where he is aboard, tender your persons to his presence, whisper him in your behalfs. (1863)

However, unlike many of the other survey categories, neither guy nor
gal was opposed to having their significant other make that cinematic
decision on their collective behalves. (2003)

Attribution
Source : Link , Question Author : ohwilleke , Answer Author : KumaAra