Mr. C. W. Peach on the Sea-Cup. 29 



shell-fish/' and having nowhere, in the few books I have ac- 

 cess to, seen that contradicted, I beg to forward to you some 

 observations on the subject, and to show that the " sea-cup " 

 does not belong to the periwinkle, but to the Purpureas la- 

 pillus. In the early part of January of the present year I 

 found that the Purpureus lapillus was very abundant on the 

 rocks in Little Peraver near my residence, and that they got 

 together in clusters. I watched their movements, and found 

 that where they assembled the u sea-cup " was plentiful in- 

 deed ; in fact I never before saw them so abundant. On taking 

 hold of some of tlje whelks, I found that they covered three 

 or four of the u cups " with their mantles, and it required a 

 good pull to remove them. I also noticed that there were in- 

 dentations in the mantle corresponding with the number of 

 " cups " which it had enveloped, and that when the shell was 

 removed a drop of transparent matter stood on the upper end 

 of each cup. After the whelk has formed and filled them, the 

 mouth is securely sealed up. The " cup " is then of a pale 

 yellowish colour ; the internal part soon assumes a granular 

 appearance which becomes more and more distinct; after 

 some time, some of them change to a pinkish hue, and the 

 young fry can be better distinguished ; the thickened seal of 

 the operculum becomes thin, and after about four months 

 opens, and the young prisoners escape into the surrounding 

 medium, and take refuge in crevices of the rocks or amongst 

 mussels, Balani, &c. &c. which are attached to them. The 

 young leave the " cups " gradually, and sometimes a fortnight 

 elapses between the exit of the first and the last, and they are 

 of different sizes ; they have all the peculiar habits of the adult 

 ones, such as remaining out of the water for long periods : this 

 I observed in many that I reared in a dish in my house ; some 

 of them also were of a purple colour. Some which I took 

 out of the " cups " — nay, all — show the distinguishing canal, 

 and are at first semitransparent and horn-coloured : the older 

 before leaving the * cups," the more white and opake they 

 are, and show the striae and markings on the pillar, with the 

 canal, and all the characteristic appearances of the old shell, 

 clearly evincing that they belong to the Purpureus lapillus, 

 and not the Turbo littoreus, which latter shell has no canal 

 or markings on the pillar. 



I observe also, that in Little Peraver, where the "egg-cups" 

 and Purpureus lapillus are abundant, there is scarcely a peri- 

 winkle to be found ; whilst at Cologna in the same parish, 

 about half a mile distant, where periwinkles are numerous, 

 and the Purpureus lapillus very scarce, egg-cups are few and 

 far between. A > 



