G. O. Sars. 



1. Apus numidicus, Grube. 



Several beautifully preserved specimens of this form, 

 males and females, were sent to me by Dr. Purcell, having 

 been collected in 1897 by Mr. J. L. Drege at Port Elizabeth. 

 They agreed exactly with the specimens raised by me here 

 in Christiania, and described in my first paper. The length 

 of the largest male specimen measured (not including the 

 caudal filaments) 30 mm., or about the same as the largest 

 specimen previously examined by me. The number of caudal 

 segments in all the specimens was that formerly indicated 

 by me, viz., in the females 11, in the males 14. 



2. Apus namaquensis, G. O. Sars, n. sp. 



(PL I, figs. 1—8). 



Specific Characters. — Carapace comparatively small 

 and much depressed, broadly cordiform in outline, with the 

 greatest width rather behind the middle, front narrowly 

 rounded, hindmost part abruptly constricted, with the terminal 

 lobes appressed and acutely produced,posterior sinus semilunar, 

 with the marginal denticles obsolete, surface perfectly smooth, 

 cervical sulcus and dorsal keel strongly marked, shell-glands 

 very conspicuous lying beneath a well-marked sabre-shaped 

 eminence on each side of the carapace. Eyes and post-ocular 

 tubercle about as in A. numidicus. Exposed part of body 

 very slender, cylindric, being in male nearly twice as long as 

 the median length of the carapace. Caudal (not pedigerous) 

 segments in female 14, in male 18. Caudal filaments of 



