20 



and the two outer ones reduced to a row of dots, we have rar. Johnstoni. 

 The dark mai-kings may become so prominent as to give the animal the 

 appearance of having five light stripes ; this is var. fasciata. If the dark 

 markings entirely coalesce, so that the ground colour is entirely 

 obliterated, the animal appears unicolorous, and is var. obscura. There 

 are various other varieties, but these are quite sufficient for mention. It 

 will have been seen that the stripes of the body may be broken up into 

 spots ; but there has never been an instance known in which the spots of 

 the shield have merged into stripes ; the only way these vary is by being 

 confused into marblings. In this way L. maximus, even very young ones, 

 may always be distinguished from Limax arbot-um, which at all ages 

 has always a dark stripe down each side of its shield. It was pointed out 

 that not much importance is attached to the numerous colour-variations 

 spoken of, although it was necessary — for clearness and precision— to give 

 them names. In the present state of biological science the study of 

 variation is all-important, and the most trivial ones are by no means to be 

 neglected. Passing to other parts of the subject, it was stated that fossil 

 forms are not known, and that this species does not extend its range so 

 high up the mountains as L. arborum or Avion ater do. In the English 

 vernacular this species has been called the great slug, from its size, and 

 the leopard slug, from its often being spotted. In conclusion, he stated 

 that he would be glad to receive specimens of slugs in general from 

 all parts of the country, especially Scotland and Ireland, as he and 

 J. W. Taylor were studying their distribution and variation, a task for 

 which a liberal supply of material is indispensable. His remarks were 

 illustrated by many drawings and living and preserved specimens, and 

 numerous microscopic slides of the palates of mollusca. 



June 5th, 1886. 

 J. STUBBINS, F.G.S., F.R.M.S., on " FORAMINIFERA." 



The literature on this subject is so voluminous that a historical 

 summary is simply impracticable, but one interesting fact is that all the 

 observers in this field of research, between the first English record, that 

 of Hooke in 1G65, to 1826, when D'Orbigny appeared, fell into one common 

 error, viz., that they placed the Foraminifera among the mollusca, from a 

 resemblance in some of the forms to the Nautili, until Dujardin in 1835 

 asserted their affinity to the Retiailarian rhizoimda. 



Modern writers have by common consent classified them, in conformity 

 with charactei's derived from their shells, into three sections — two calcareous 

 and one arenaceous. The first division, the Imperforata, have shells of an 

 " opaque calcareous substance, having a porcellaneous aspect," and exhibit 

 a brown or amber hue by transmitted light. Some Miliola?, from soundings 

 4| miles in depth, dredged during the Challenger expedition and described 

 by Brady, have a "delicate homogeneous silicious investment," which 

 suggests an affinity to the Polycystina, 



