2 [June, 



circular, and there is a deep open umbilicus ; all have the mouth 

 perfectly open. Upon making a vertical section, it is seen that the 

 whorls are perfectly separated. They are of extreme lightness, 

 yet the walls are nearly li mm. thick. This lightness is owing 

 to the texture, which, although perfectly hard and firm, is some- 

 what fibrous. The material is undoubtedly vegetable matter, but 

 whether masticated specially for* the purpose, or excrementitious, is 

 uncertain to me. I rather incline to the latter idea, because there 

 is no opening through which the excrement could be ejected, other 

 than the mouth of the case. The exterior has a thin coating of 

 (apparently) silk of a pale drab colour, which renders the cases 

 very smooth, but not glossy ; but the older cases are blackened by 

 a coating of what is probably adventitious matter. I am unable to 

 say on what plant they were found, but one of them is attached (at a 

 point indicated in the top right-hand figure) to a fragment of a plant, 

 which may possibly be Mimosa. 



It is well known that exotic species of PsycliidcB are given to 

 fabricating cases of extraordinary forms, but, of all that I have seen, 

 these are the most extraordinary, on account of their perfect simi- 

 larity to shells. 



The cases of the South European Psyche {Cochloplanes) helix, 

 are tolerably familiar to most entomolo- 

 gists, but their resemblance to shells is 

 less marked, on account of the debris 

 with which their exterior is covered ; 

 moreover, the texture is slight and yield- 

 ing, and at, or near, the apex there is an 

 opening through which the excrement 

 can be ejected. They bear more ex- 

 ternal resemblance to the now well-known 

 cases of the Trichopterous . genus Heli- 

 copsyche. For the sake of comparison, I 

 give here figures of the cases of Psyche 

 helix. 

 The figures are enlarged to two diameters, but the smallest figure 

 on each block (indicated by *) shows the natural size. 



With the above-described cases collected by Dr. Baxter are others 

 formed of twigs, arranged longitudinally or transversely (not uncom- 

 mon), and one, 47 mm. long, mimicking a shell of the genus Dentalium, 

 but such. I think, have already been noticed and described. 



Lewisliam, London : 



May, 1884. 



