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THE VOYAGE OF H.M.S. CHALLENGER. 



Synopsis of the Genera of Lithocampida. 



Subfamily 1. STICHOCORIDA, Haeckel, 1881, Prodromus, p. 438. 



Definition. L ithocampida with the terminal mouth of the shell open (vel 

 Stichocyrtida eradiata aperta). 



Genus 642. Lithostrobus, 1 Biitschli, 1882, Zeitschr. f. wiss. Zool., vol. xxxvi. p. 529. 



Definition. Stichocorida (vel Stichocyrtida eradiata aperta), with conical 

 shell, gradually dilated towards the wide open mouth. Cephalis with a horn. 



The genus Lithostrobus is probably the most primitive among the Lithocampida, 

 and comprises those forms of this family in which the slender, conical shell is gradually 

 dilated towards the wide, terminal mouth, each joint being broader than the preceding. 



1 Lithostrobus = Cone of silex; X/0of, orjo'/Sof. 



