274 JOURNAL OF CONCHOLOGY, VOL. 15, NO. 9, MAY 1ST, I918. 



visable. I have now discovered bj' somewhat painful experience that 

 the success or failure of rearing a batch of newly hatched shells depends 

 upon being at hand on the day of rheir hatching and being able to give 

 them a slight shower-bath and some fresh food. With a good start 

 all will probably go well, but once let the youngsters seal themselves 

 on to the side of the box or glass and it is almost impossible to get 

 them to feed. The nature of the sand kept in the bottom of the box 

 is another matter for care. At great trouble to himself my friend 

 Mr. Robert J. Welch brought me some pounds' weight of sand from 

 Rosapenna in Co. Donegal, which being highly calcareous we thought 

 would help greatly. Mortality soon increased and the shells were 

 subject to much malformation, but it was not until nearly two years 

 later that I traced the cause to the sand. The supply having run out, 

 some local Co. Down siliceous sand was used, lime being provided by 

 a lump of old mortar, and the health and shell-forming activity quickly 

 improved. I believe the injuries were caused by the presence in the 

 Rosapenna sand of multitudes of sponge spicules as well as the broken 

 spines from the tests of sea urchins. Not only did these spines 

 injure the mantle and consequently the making of shell, but I 

 believe that they actually caused the death of many individuals by 

 becoming embedded in the walls of the intestines. It is necessary, 

 perhaps, to state what has often been pointed out before, that the 

 sand is actually eaten by the snails, the chief purpose being, of course, 

 to obtain lime. This brings me to a statement of long standing often 

 copied by modern writers, I fancy without personal verification, 

 namely, that the young snails bury the mouth of their shells in the 

 sand while the shell is being added to. All my experiences point to 

 the conclusion that they do this to obtain lime befo?-e 7naking shell 

 but that the shell is added to when they are on the glass or on the 

 sides of the box, in other words when there is no chance of anything 

 touching and injuring the newly formed shell. The following data 

 relating to the rate of growth of the shell may be interesting. They 

 refer to notes on the growth of one of the roseozonata in Experiment 

 No. 5, which was selected as a parent for the F2 "B" generation: — 

 "The 00345 specimen came out of hibernation on 28th February, 

 1913; on 5th March it had added an eighth of an inch of new shell 

 and by each of the following dates a further eighth of an inch had been 

 completed, 12th, 21st, and 30th March, 7th and i6th April." On 

 the last date the lip was commenced and this was perfectly completed 

 on the 25th of May, as nearly as could be ascertained. During this 

 time so far as I was aware the animal never buried itself in the sand 

 and when not feeding remained quiescent and attached to the side of 

 the box. One more point of interest may be touched on briefly. 

 The colour of some of the newly hatched H. nemoralis has been 



