•Quarterly Journal of Concliology. 95 



as their parents and offspring to the same extent as we observe in 

 the case of our own kind." (p. 17) Whilst if they are not found 

 together, and H. Jiortensis is only a variety, how is it that the 

 variety becomes permanent ? Do not shells follow the same Taws 

 as other animals in returning back to the original stock, or in 

 throwing off other varieties which differ from the variety itself as 

 much as it differs from the typical species ? But, as H. hortensis, 

 when living by themselves, propagate animals resembling them- 

 selves, and those from which their parents sprang, they also, in 

 conformity with the above definition, must be considered as species. 

 Another reason Jeffrey.s gives for not considering them distinct 

 species, is that they are connected by the intermediate form, hybrida 

 but as we shall see presently, the fact of there being no interme- 

 diate form is not always allowed to separate species. Some of the 

 specimens of H. ri/fescens & Jiispida are exactly alike to my limited 

 powers of observation. I have compared them for a long time 

 without being able to find any distinguishing character. In addi- 

 tion to these, there is H. depilata of Gray, and H. conciniia of 

 Jeffreys. The latter one differs trom hispida in being more glossy, 

 and never globose, and in the umbilicus being considerably more 

 open. These constitute two species. On the other hand, H. 

 rufescens has its spire short and blunt ; and another, as described 

 by Jeffreys, has a smaller shell, and the spire more raised. But 

 this is only made a variety ( H. rufescens vai: iniuor). It is thus 

 next to impossible to discover the principle upon which concholo- 

 gists proceed in manufacturing their species. This will appear 

 more strongly in two other genera — first, the genus Clausilia, here 

 there are four species, one of which C. laniinata is separated at 

 once from the rest, by Jeffreys, in consequence of its shell being 

 nearly smooth, and in having its clausilium notched. It very 

 much resembles C. biplicata, but differs fiom it in its teeth, spire, 

 and other details, which may, or may not, entitle it to be considered 

 a distinct species from biplicata. But distinctions such as these do 

 not always make a species. Thus in Carychium luiuimuni, Reeve 

 (p. 127) says, " Authors are pretty well agreed that all the varieties 

 of the little glassy shell, known throughout Britain as C. vtiniuiuvi, 

 belong to one and the same species. Some specimens are smooth, 

 others are obviously finely striated, and the teeth are more conspic- 

 uously developed in some specimens than in others, while the whorls 

 vary a little in their shorter or more elongated mode of convolution.'' 

 Neither Jeffreys, Gray, nor P'orbes and Hanley give any varie- 

 ties. The latter mentions that it has a variety, but gives it no 

 name. Why are not some of the differences sufficient, at all 

 events, to make a variety ? In Azeca and Zua differences slight 

 as the above, constitute two distinct species, according to Jeffreys 

 — -two genera according to other conchologists. The former united 

 them in one genera, under the name of Coclilicopa, considering that 

 the fact of Azeca having teeth, and Zua none, is not sufficient to 



