§7 



The exopodite of the first pair of feet is composed of two joints. The second and third 

 joints are completely fused together. The junction of the two joints is defined by an outer-edge 

 spine. The endopodite is one-jointcd. 



The exopodite of the second pair of feet is three-jointed. The endopodite is two-jointed. 

 The second joint of the endopodite is furnished with three transverse rows of spines. 



The exopodites and endopodites of the third and fourth pairs of feet are three-jointed. 

 The second and third joints of the endopodite of the third pair of feet are each furnished 

 with two transverse rows of spines. The second joint of the endopodite of the fourth pair of 

 feet is turnished with one transverse rovv, and the third joint with two transverse rows of spines. 

 The surtace of the joints is closely set with minute points. 



The fifth j^air f f ee t J s very small and rudimentary. Each foot consists of two free 

 joints attached to a basal part. The second joint is moderalely stout and spiniform (Plate 

 XXXIII, fig. 9). 



Occurrence. — One specimen was obtained from the plankton collected with the 

 Hensen vertical net at Station 143, 1000 metres to the surface. 



This species appears to be identical with the form described by Sars (1907^). The only 

 difference that can be made out between the preliminary description, and that now given, is 

 in the jointing of the endopodite of the third pair of feet. Sars states that it is two-jointed, 

 whereas in the 'Siboga' specimen it is distinctly three-jointecl. It also appears to be identical 

 with Amallophora dubia, described by my father from males only, that were found in plankton 

 collected in the Gulf of Guinea. The two large amalla on the apex of the first pair of maxilli- 

 pedes, are clearly shewn amongst the other illustrations (Plate IV, fig. 13) in the report, '< )n 

 Entomostraca' from the Gulf of Guinea. 



I have included Amallophora and Heter amalla in the family Phaennidae, as the sensory 

 appendages on the apex of the first maxillipedes are quite distinct from those found in the 

 family Scolecithricidae. The ciliated heads indicate a closer relationship to Phaenna than to 

 Scolecithrix. 



8. Family Scolecithricidae. 

 Genus Scolecithrix Brady, 1883. 



Brady established this genus for the reception of a Calanoid form described by Lubbock 

 as Undina danae, which is distinguished by the presence of a tuft of worm-like sensory filaments 

 on the apex of the first pair of maxillipedes. The fifth pair of feet is entirely absent in the female. 



A second form, Scolecithrix minor, with a fifth pair of feet in the female, was also 

 included under the genus by Brady. Giesbrecht and Schmeil subsequently included a number 

 of species under the genus, the females of which are furnished with fifth feet. Sars rightly 

 points out, however, in 'Crustacea of Norway', that the inclusion of Scolecitlirix-Wke forms with 

 a fifth pair of feet is erroneous, and established a new genus for the reception of some of them. 



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