248 



DISCOVERY REPORTS 



a very southern station near the South Shetlands, with rather cold water, the tempera- 

 ture is not a factor of very great importance in its distribution. 



Supplementary Description. The species is represented in this collection by very 

 typical specimens from four different stations. The specimens have umbonal teeth on 

 both scuta, which is given as very characteristic for this species. The very closely related 



Fig. 10. Lepas anslralis {a-f from St. 63). a. Pupa (total length 2-55 mm.), b. Pupa with pri- 

 mordial valves and initial development of peduncle (total length 3-15 mm.), c. Young specimen just 

 leaving the Cypris valves (total length 3-35 mm.), d, e, f. Young specimens with initial development 

 of the calcareous plates (total lengths 3-55, 4'07, and 4-30 mm. respectively), g. Full-grown specimen 

 from St. 212 (total length 64 mm.). h. Carina, i. Carina seen from beneath, j. Scuta, ventral view. 



L. anatifera sometimes has umbonal teeth on both scuta, but there is yet a difference, 

 for in L. australis the scuta are more curved in the umbonal part. It may here be pointed 

 out that these teeth can also disappear during ontogeny, as I have found in some speci- 

 mens from Juan Fernandez Islands. They were described as var. weltneri (Nilsson- 

 Cantell, 1929). But, in typical L. australis, there is no variation in the teeth of the scuta 

 as in L. anatifera. As other good characters for L. australis may be mentioned the very 

 thin plates of the capitulum and the well-developed prongs on the carina. 



