LAS^A. 221 



L. rubra has been recorded by Sars among arctic shells 

 occurring in newer tertiary strata in the diocese of 

 Christiania. 



Dr. Turton was the first who noticed the curious fact 

 that this minute mollusk is viviparous. It does not 

 appear to be prolific, as seldom more than twenty young 

 ones are to be seen at any one time in the shell of the 

 parent. They are fully formed while in this stage of 

 growth, and their shells have even a tinge of purplish- 

 red on each side of the beaks. Mr. Clark says the 

 ovary contained no young in specimens which he pro- 

 cured in the winter. The same may perhaps be said of 

 most mollusca, whether viviparous or oviparous, as well 

 as of other animals the season of whose loves in a state 

 of nature does not commence until 



" species patefactast verna diei, 



Et reserata viget genitabilis aura favoni." 



A discussion took place some years ago, between 

 Mr. Clark on the one side, and Messrs. Alder and Han- 

 cock on the other, as to the use of the anterior tube in 

 this species and in Kellia suborbicularis, both of which are 

 viviparous. Mr. Clark contended that it was an organ 

 of reproduction, in consequence of his having observed 

 the fry ejected through it. His opponents disputed this 

 uterine function, and showed that the tube serves to 

 convey water to the gills. My own observations induce 

 me to believe that it has various uses — one for obtaining 

 food, another for aerating the gills, and a third for the 

 expulsion of the fry. The tube seems to be expanded 

 or contracted at the will of the animal, being formed 

 merely by an overlapping of the folds of the mantle. Its 

 sides are never united. The present species is rather 

 active in its habits. According to Mr. Clark, it imme- 



