168 DISCOVERY REPORTS 



results of a study of the animals of British Ianthina and the effects of growth on shell contour. These 

 results will together give a clearer view of the interrelations of the various forms included in the 

 species of Ianthina, and in particular of the influence of life-history on shell form. 



Fig. I. Sketches of the shells of Ianthina ianthina (L.) (a, b, c) and of /. globosa Swainson (d) to show characteristic range 

 of form, (a) I. ianthina. The typical communis-iorm (Winckworth Collection, Madras), (b) I. ianthina. The planispirata- 

 form, view from above and in side view, (c) I. ianthina. View of the balteata-form, showing the periphery and strong labial 

 sinus characteristic of the species (shell from WS 1057). (d) I. globosa. Three views of shells from the Winckworth 

 Collection (Brit. Mus.). 



Order MESOGASTROPODA 

 Unidentified prosobranch larval shells 



The three sets of inshore stations, WS 980 and WS 981, off Walfisch Bay, WS 988 and WS 989 off 

 Sylvia Hill, and WS 1002 at the mouth of the Orange River, each yielded shells of a gastropod veliger 

 larva and of lamellibranch larvae. The gastropods at all three stations were of the same species, which 

 — owing to the retraction or loss of the velar lobes and damage to the shell after preservation— were 



