A new species of Euchirella (fam. Aetideidae) from the "Dana"-collections (Copepoda, Calanoida)

SUMMARY Euchirella paulinae spec. nov. is described and illustrated in extenso ; various structures are outlined in detail for the first time. The external morphology of the new species is discussed with reference to the other species of the genus. Some brief remarks are made about the anatomical terminology of the mouthparts of Copepoda, and on the necessity to always describe new species really scrutinously. INTRODUCTION In the course of a revision of the aetideid genera Euchirella Giesbrecht, 1888 and Pseudochirella G. O. Sars, 1920, an undescribed species of Euchirella was found in the material originating from the Danish "Dana" Expedition 1928-30. The new species will be reported upon separately in the present paper. Its tentative relationships with the other species of the genus will be dealt with in a forthcoming study on Euchirella, while detailed accounts of the taxonomic value of several morphological structures, e.g., of the oral field, of the various mouthparts, and of the genital field, are in preparation. All specimens are preserved in 70% alcohol (ethanol), while dissected appendages have been mounted on slides in Berlese's Fluid. Observations on specimens in situ were made both under dissecting microscope and compound microscope, with the specimens in mono-ethylene-glycol. Preparations for the scanning electron microscope were made by air-drying after transfer through 96% alcohol and by sticking the parts on stubs provided with double-sided adhesive tape. The scan preparations were coated with one thin layer of gold only. Ultrasonic cleaning was applied to fouled specimens, if necessary.