248 DR, T. ALCOCK ON POLYMORPHINA TUBULOSA. 



in having numerous large holes, arranged in several rows 

 radiating from the mouth towards the hase of the shell, 

 exactly as in undoubted specimens of P. tubulosa ; but 

 they are without the slightest trace of the external arched 

 coverings and tubular branches. These might at first 

 sight be set down as very much rolled and worn specimens 

 of the ordinary P. tubulosa ; but there is no evidence in 

 the Dogs Bay sand of other kinds of foraminifera being 

 worn to the extent which would be necessary to produce 

 such a result ; and the suggestion is uncalled for in this 

 particular case, since it is evident that, at one part of the life 

 of the animal, its shell must have presented the appearance 

 of these specimens — unless it could be admitted that the 

 holes are formed after the production of the shell covering 

 on the expanded pseudopodia. But this last is clearly a 

 single act, and its plan is evidently not such as would be 

 adopted if the protection of sarcode were the object in 

 view — the subdivision into many projecting branches most 

 delicate and fragile at their points exposing it as much as 

 possible to every injury, and therefore presenting a form 

 and arrangement not at all likely to promote the comfort 

 and gonvenience of the animal if it were to exist long in 

 that state ; and when to this we add that the pseudopodia, 

 which are the means by which the foraminifera communi- 

 cate with the external world, are sheathed by their shell 

 covering so as to be incapable of action, and, moreover, 

 that every part of the animal becomes completely enclosed, 

 the conclusion seems inevitable that this is not a condition 

 in which it passes any considerable portion of its life, but 

 that it is, as already suggested, merely the closing and 

 final act. The holes through the thick shell, however, 

 present a difiierent history ; they show, by the quantity of 

 shell-material removed, and by the way in which separate 

 holes have run together, that time has been spent in their 

 formation ; and they have also a clear and intelligible use 



