On a Stygiomysis from the West Indies, with a note on Spelaeogriphus (Crustacea, Peracarida)

Abstract

Stygiomysis holthuisi (Gordon), the second known species of the aberrant Mysidacean genus Stygiomysis, is described and figured in detail. The systematic position of the family Stygiomysidae is discussed. It is most closely allied to the family Lepidopidae and both families possess certain characters of the suborder Mysida, others of the suborder Lophogastrida. The paragnatha of some other Mysidacea are figured for comparison with those of Stygiomysis. The terminology of the thoracic limbs, and of the segments of the thoracic endopodite, is briefly discussed. A note on Spelaeogriphus lepidops Gordon is added, together with a few comments on the systematic position of the order Spelaeogriphacea.