請觀音經疏闡義鈔 2.64

2.64

「列凡夫眾」者，順古立名也。若準今家，應云「雜眾」，以其中凡聖兩兼、道俗相間故。「即有八部名四種眾」者，即經云「四眾、天龍八部」。天謂欲色諸天。龍是畜趣，正報似蛇，依報如天，亦能變為人像。八部，即四天王所領，東方領二鬼，揵闥婆、富單那。南方領二鬼，薜荔多、鳩槃茶。西方領二鬼，毒龍、毘舍闍。北方領二，夜叉、羅剎。共領八部，不令惱人。四眾者，舊云出家在家各二，合為四眾。此名局，意不周。今於一眾更開為四，即各有當機等也。

"Listing the assembly of ordinary beings" conforms to the old designations. According to our school, it should be called the "miscellaneous assembly," because it includes both ordinary beings and noble ones, and the monastics and the laity are intermixed. "Namely, having eight classes [of beings] called the four kinds of assembly": this refers to the sūtra's words "the four assemblies, the heavenly beings, dragons, and eight classes." "Heavenly beings" refers to the heavens of the desire and form realms. "Dragons" are of the animal rebirth destiny; their primary fruition resembles a snake, but their dependent fruition is like that of the heavens, and they can also transform into human forms. The eight classes are those overseen by the Four Heavenly Kings: the eastern direction oversees two kinds of spirits, gandharvas and pūtanas; the southern direction oversees two kinds of spirits, pretas and kumbhāṇḍas; the western direction oversees two kinds of spirits, poisonous nāgas and piśācas; the northern direction oversees two kinds of spirits, yakṣas and rākṣasas. Together they oversee the eight classes, not allowing them to afflict humans. As for the "four assemblies," in the old tradition it was said that monastics and laity each have two, combining to make four assemblies. This designation is limited and its meaning is incomplete. Now, within each assembly, it is further opened into four, meaning that each has those who are the direct addressees and so forth.