REPORT ON THE COPEPODA. 31 



sexes; and possessing no hinge joint : those of the male are provided with thickened, club- 

 shaped appendages, and the joints are often slightly narrowed at the base. Posterior antennae 

 two-branched, the secondary branch haying three or four small intercalated median joints. 

 Maxilla composed of abroad masticating portion, which bears a series of stout, short seta), 

 and a foliaceous, multifid palp made up of several digitiform segments, all of which bear 

 numerous long and finely ciliated setae. Mandibles large and strung, dilated and strongly 

 toothed at the apex ; basal joint of the palp large and widened towards the apex, from 

 which spring two nearly equal branches, composed (usually) of two, and three or four, 

 joints respectively. Anterior foot-jaws broad and strong, provided with several marginal 

 processes which bear strong curved setae ; posterior foot-jaws elongated, composed of two 

 large basal and five smaller apical joints, all of which bear long setae. Five pairs of two- 

 branched feet adapted for swimming, each branch composed of three joints ; in the male, 

 however, the outer branches of the fifth pair on one or both sides are somewhat modified. 

 Abdomen of the male five, of the female four-jointed. 



The genus Calanus was established by Leach for the reception of the species called 

 by Miiller, in his Entomostraca, Cyclops longicomis, and in the Zool. Dan. Prodr. 

 Cyclops finmarchicus, and identified by that author with Gunner's Monoculus Jmmar- 

 chicus. It is impossible to say certainly what is the species referred to in Midler's figure. 

 The caudal part has, I think, undoubtedly been drawn from Temora Jinmarchica, Baird, 

 while the antennae are much too long for that species, and are probably taken from 

 Cetochilus septentrionalis, Goodsir, which species seems also to be meant in the descrip- 

 tion : — " Antennae, — corpore longiorcs." But Gunner's figures, from the general contour 

 of the animal, the length of the antennae, and the characteristic long subapical setae, 

 certainly belong to Cetochilus septentrionalis. I therefore follow Boeck in assigning the 

 generic term Calanus to the form originally described by Gunner, discarding the later 

 name Cetochilus. Baird's Temora Jinmarchica will in this ease stand as the type of 

 the genus Temora. In accordance with this view it is impossible to accept Dr. 

 Baird's identification of his Temora Jinmarchica with Gunner's species. And though 

 the generic name Temora holds good, it seems best, considering the doubt which 

 must rest upon the meaning of Midler's figure, to discard the name longicomis (adopted 

 by Boeck and by myself in the Monograph of the British Copepoda — from Miiller) 

 and to accept that of longicaudata proposed in 1857 by Sir John Lubbock. I have 

 thought it best to give in detail my reasons for this nomenclature, inasmuch as a 

 different course is advocated by Dr. Claus, and, I think, by Giesbrecht. 



As understood by Dana, this genus includes a great number of species properlv refer- 

 able to several distinct genera, notably to Cala nits (proper), Hemicalanus, Eucalanus, and 

 Temora, but it is not possible in many cases to assign Dana's species to their true position, 

 the published details being insufficient for that purpose. The presence of five pairs ,,f well- 

 developed swimming feet in both sexes, and the peculiar modification of the fifth pair 



