Bittium watsoni var. dissimilis Sykes, 1925 accepted as Bittium watsoni (Jeffreys, 1885) (original description)
Caecum achates Sykes, 1925 (original description)
Cerithiopsis concinna Sykes, 1925 accepted as Narrimania concinna (Sykes, 1925) (original description)
Cerithiopsis papillaris Sykes, 1925 (original description)
Cithna excavata Sykes, 1925 accepted as Xyloskenea naticiformis (Jeffreys, 1883) (original description)
Cithna marshalli Sykes, 1925 accepted as Iphitus marshalli (Sykes, 1925) accepted as Iphitus tenuisculptus (G. Seguenza, 1876) (original description)
Homalogyra aperta Sykes, 1925 accepted as Eudaronia aperta (Sykes, 1925) (original description)
Homalogyra granulosa Sykes, 1925 accepted as Retigyra granulosa (Sykes, 1925) (original description)
Homalogyra marshalli Sykes, 1925 accepted as Neusas marshalli (Sykes, 1925) (original description)
Homalogyra sinuosa Sykes, 1925 accepted as Adeuomphalus sinuosus (Sykes, 1925) (original description)

Moroccan part of the Strait of Gibraltar for Caecum achates Sykes, 1925 
Portuguese Exclusive Economic Zone for Cithna marshalli Sykes, 1925 
Portuguese Exclusive Economic Zone for Homalogyra aperta Sykes, 1925 

 Taxonomy

 for Caecum achates Sykes, 1925

Allied to Caecum cuspidatum Chaster, 1896 [details]

 Taxonomy

 for Cerithiopsis papillaris Sykes, 1925

is a species of Dizoniopsis [details]