PTEROPODA. MASSY. 



217 



Antarctic (Ross Sea and neighbourhood). 



Station 274, one. 

 275, two. 



284, thirteen. 



285, three. 



289, *w. one hundred and eleven. 

 290, tuciit y-tliree. 

 Antarctic (McMurdo Sound). 



"Discovery" Exp., 1901-4, 3 metres. 



Feb. 19, 1904, one. 

 Station 317, June 28, ca. four hundred 



and twenty, average 1 nun. 

 Station 317. Aug. 8, <'<i. nine hundred 



and fifty, average 1 mm. 

 Station 326, ca. fifty, about 1 mm. 

 333, three, 2 mm. 

 342, thirty-two, 2-3 mm. 



350, sixteen, about '75 mm. 



351, Apr. 30, 10 metres, <</. 



three thousand. 



Antarctic ( Mc.Mm-do Sound). 



May 2, 30 metres. <;<>. two 

 thousand. 



May 1 3. <-ii. five thousand 

 six hundred. 



May 18, 10 metres, ca. 

 nine hundred. 

 May 19, 30 metres, ca. 

 one thousand four hun- 

 dred. 



May 20, 50 metres, ca. 

 one thousand nine hun- 

 dred. 



May 21, 100 metres, ca. 

 i lirce thousand four hun- 

 dred. 

 ,, JMay 22, 150 metres, ni. 



four thousand. 



,, 354, ca. eight hundred and fifty. 

 357. cd. three hundred. 



The above thirty-four hauls, comprising a rich material of some twenty-seven 

 thousand individuals would certainly seem to be sufficient for the most exhaustive 

 study. As in the case of the specimens obtained by the " Discovery " Expedition, and 

 referred by Sir (A Eliot to L. antun-fiat, Woodward, the shells are, however, in many 

 cases either absent or partially eroded, or much broken. Boas (1886, p. 42) considered 

 the shells of this species to be more friable than that of any other species of this group 

 known to him. The "Terra Nova" specimens varied in size from '50 to 6 mm., the 

 vast majority, however, measured from 1-2 mm. The shells (hyaline with faint spiral 

 striae) were only present on specimens up to a size of 2 '50 mm. In no case was there 

 a trace of the umbilical border typical of well-preserved shells of moderate sized 

 specimens of L. lu'licinn. Bars (1878, p. 329) mentions and figures the umbilical 

 border, and states that none of the specimens which were seen by him exceeded 4 mm. 

 Meisenheimer (1905, p. 410) found with regard to the Arctic specimens which he 

 examined that the umbilical border was very well marked in the shells of adult 

 animals, but in the case of younger (of about 3 mm. in diameter) it was, on tin- 

 contrary, only very I'eelilv developed. Sir < '. Hliot (1907. p. 7) drew up a table 

 containing six points of difference which he observed to be constant between tin- 

 Antarctic specimens obtained by the " Discovery," which he referred to L. n/itiirffii-n, 

 and a large collection of specimens of L. /n/icinn from Davis Straits and the North 

 I'acitic. In the first plai e he found that L. n/i/nn'/ii;/ was smaller and possessed tins 



