found: Syn. liv. org.:v. 2, p. 169 (Pycnogonida. Class (or subphylum) of arthropods of chelicerate stock; pycnogonids) p. 172 ("... it is difficult to agree upon classification above the generic level, and some specialists cannot recognize divisions of ordinal rank. The usual practice in systematic treatises is to treat the Pycnogonida as a class or superphylum [i.e. subphylum] without orders and to proceed directly to the families.")
found: Concise encyc. biology, 1996(Pycnogonida, pycnogonids, Pantopoda, sea spiders: a class of arthropods)
found: The concise Oxford dict. of zoology, 1991(Pycnogonida (Pantopoda; sea spiders; phylum Arthropoda, subphylum Chelicerata). A class of marine chelicerates; pycnogonids)
found: Stachowitsch, M. The invertebrates, c1992:p. 487 (Pycnogonida (Pantopoda); sea spider, pantopod, pycnogonid)
found: ITIS, Apr. 25, 2000(Pycnogonida. Common name: sea spiders. Rank: Class. Subphylum Chelicerata, Phylum Arthropoda)