PROM THE GULF OF GUINEA. 139 



side by side, extending from the posterior extremity, but becoming obsolete towards the 

 anterior end, where they run out into shallow circular depressions ; the front margin is 

 marked with a number of impressed, short, radiating lines. Length -8 mm. (l-31st of 

 an inch). 



Habitat. Loanda Harbour, in a surface tow-net gathering, collected February 13th. 

 One specimen only obtained. 



This species closely resembles Cijtlicre costellata, lloemer, an ostracod obtained fossil 

 in the Tertiary deposits of England and also in France. 



Xestolebeuis, G. O, Sars (1865). 



Xestolebekis (?) MARGARiTEA (Brady). 



18G5. Cytheridea margaritea, Brady, Trans. Zool. Soc. vol. v. p. 370, pi. Iviii. fig. 6, a, b. 



1880. Xestokbtris margaritea, Brady, Report ou the ' Challenger ' Copepoda, p. 127, pi. xxx. fig. 2, a, h. 



Habitat. Lagoon, Sao Thome Island, in a surface tow-net gathering, collected January 

 27th ; several species were obtained. 'IlhaXestoleberis now recorded, when viewed laterally, 

 differs from X. margaritea described and figured hi the ' Challenger ' Pi-eport in being 

 rather more pointed at the anterior end, but otherwise it seems to agree with that 

 species ; it also agrees with the figures of the same species in the ' Monograph of the 

 Marine and Fresh-water Ostracoda of the North Atlantic and North-western Europe,' 

 by Brady and Norman, ji. 246. 



Cytherura, G. O. Sars. 

 Cytuerura simulans, n. sp. (PL XIV. figs. 52, 53.) 



Shell, viewed laterally, subovate ; greatest height behind the middle equal to about 

 four ninths of the length ; dorsal margin moderately and evenly arched ; ventral margin 

 slightly concave ; beak subcentral, obtuse, more prominent than in Cytherura similis, 

 G. O. Sars, which the species now described somewhat resembles; anterior extremity 

 evenly rounded and slightly oblique ; the outline seen from above is subovate, widest 

 behind the middle ; width equal to the height ; sides flattened centrally, converging and 

 gently curved ; anterior subtruncate behind, with the middle part shortly produced to a 

 blunt pointed apex ; anterior extremity subacuminate. Length •16 mm. 



Habitat. Loanda Harbour, in a surface tow-net gathering, collected February 13th. 

 One specimen only obtained. 



Cytheropteron, G. O. Sars (1865). 



Cytheropteron trilobitis, Brady. (PI. XIV. figs. 51, 55.) 



1880. Cytheropteron trilobitis, Brady, On Ostracoda collected by H. B. Brady in South Sea Islands, 

 Traus. R. S. E. vol. xxxv. pt. ii. p. 511, pi. iii. figs. 22, 23. 



Habitat. In a lagoon, Sao Thome Island, in a tow-net gathering, collected January 27. 

 Only a few valves of this species were obtained ; it differs very little from the ' Challenger ' 

 specimen. 



18* 



