What was it about snails that made the writer collect them for his friend on that day in particular

问题描述:

What was it about snails that made the writer collect them for his friend on that day in particular
particular不是形容词吗,怎么前面用in的啊

in particular是个短语,意思是尤其,特别
比如
The risk is that Europe will get hit harder,in particular its financial system.
风险在于,欧洲将遭受更严重的冲击,特别是欧洲的金融体系.
Some carriers are being propped up by state aid,in particular in parts of Asia and the Middle East.
一些运营商获得了*援助的支撑,特别是中东及亚洲部分地区的运营商.