224 



HARDWICKE'S SCIENCE-GOSSIP. 



religion, science, and practical work) which now 

 seem diametrically opposed and mutually subversive. 

 — P. Q. Keegan, LL.D. 



I have only to add in explanation, that my objections 

 to Homer and the poetry of the ancients apply 

 especially to their use as school books. As historical 

 records of one of the stages of human barbarism, 

 they have great archaeological interest, and the same 

 may be said, in a minor degree, of the early English 

 literature to which he alludes. In the dark ages 

 when there was no other literature available, these 

 old authors were desirable objects of study as literary 

 models ; but now that all the excellence of their art, 

 minus the depravity of their morals, may be found 

 in modern literature, I maintain that they should not 

 be chosen for the education of youth. 



Intellectual gymnastics are obtainable by the study 

 of anything demanding intellectual effort. The 

 manner of study has even more influence in this 

 respect than the subject itself. Mathematics, physics, 

 chemistry, biology, or moral philosophy may be 

 degraded by mere rote cramming for examination's 

 sake ; the same with any language or any literature ; 

 or they may be taught intelligently and philo- 

 sophically, and thus afford the highest mental 

 discipline. 



THE VARIATION 



AND ABNORMAL DEVELOPMENT 



OF THE MOLLUSCA. 



Part III. 



Terrestrial Gasteropoda. 



yj RIO N ATER.— K considerable number of 

 ■*1 forms occur ; at Bedford Park, for instance, 

 we find the type and varieties rufa, succinea, and 

 nigrescens, as well as a form which does not agree 

 exactly with nigrescens or plumbed, but is not distinct 

 enough for a name ; it is of a very dark slate colour, 

 with a dark brown margin. The variety albida 

 will probably turn up sooner or later, but I have not 

 yet seen it. It has been found in Sussex and Herts. 



At Chislehurst a form of var. succinea (yellowish, 

 tinged with orange posteriorly, and with an orange 

 margin), is found on the common among the brake 

 fern and brambles ; but in the old chalk-pit, in the 

 lower Camden valley, amongst the coltsfoot, this 

 form is replaced by the variety called pallescens, very 

 pale yellow with an orange margin. Some of the 

 little Arions are greenish, almost exactly the colour 

 of the under-surface of a Tussilago leaf. The full 

 description of one of these juvenile examples is : 

 Tentacles dark brown, mantle yellowish-white, 

 rather darker in front, body greenish-white, margin 

 of foot yellowish-white. 



A variety with a very dark brown mantle and a 

 black body occurs at Chislehurst. 



Arion hortensis. — A variable species, but (in our 

 district at any rate) less so than A. ater. The 

 ordinary banded form (called var. fasciata by 

 Moquin-Tandon) is found at Acton, Chislehurst, 

 Croydon, and many other places. The sole of the 

 foot is sometimes of the most brilliant orange. 



Some curious varieties are found at Bedford Park : 

 one is larger than the ordinary form, and grey, with 

 narrow lateral bands ; another is dark above, and 

 light at the sides, and others have already been 

 described. Some very little ones were pale 

 yellowish-red. 



A number of Continental varieties of this slug 

 have been described ; one of the most interesting is 

 var. virescens, which is greenish with black bands. 



Arion, sp. ? — Intermediate in size between A. ater 

 and A. hortensis \ yellowish, inclining to orange, with 

 brown bands placed in the same lateral position as 

 those of A. hortensis. Three specimens under a log 

 at Haslemere in company with A. ater, A. hortensis, 

 and Limax maximus, I sent two of these to Mr. 

 Roebuck, concerning which he writes as follows : 

 " The Arions are of a very dubious sort, and I, like 

 you, am uncertain what to call them ... I have 

 preserved your specimens in spirit, and pending the 

 settlement of their specific name, I am calling them 

 provisionally A. hortensis var. stibfusca." 



They seem to be distinct from A. hortensis ; and 

 Mr. C. Ashford, who has dissected both these species, 

 tells me that he finds slight but constant differences 

 in their anatomy. 



I have also taken this form at Chislehurst, where 

 three varieties occur ; the first is yellowish-white, the 

 second purplish-brown, and the third yellowish-grey 

 with a yellow margin. 



I fancy that these Arions will be found all over the 

 country in due time, and many of the records of A. 

 flavns possibly refer to this species. I have recently 

 found what I consider to be the true Arion fiavns at 

 Kingsley, Staffordshire. It is not unlike A. hortensis, 

 from which, however, it differs in being orange- 

 yellow on the sides and mantle and greyish on the 

 back. There are faint lateral bands. The slime is 

 orange-yellow and very thick. The sole of the foot 

 is white and translucent. The respiratory orifice is a 

 little in front of the central line of the mantle. Mr. 

 W. D. Sutton, in the "Journal of Conchology," vol. i. 

 p. 26, records what is evidently the same form from 

 Northumberland and Durham ; he says : " A variety 

 (of A. hortensis) or possibly a species, nearly allied to 

 this is found in woods. It is about twice the size of 

 the garden slug, and its colour invariably yellowish 

 fawn, inclining to amber, with a brown band on each 

 side. The two kinds are not found mixed, one 

 inhabiting the woods, and the other the cultivated 

 grounds." However, I found the two kinds 

 together at Haslemere, as stated above. 



Limax agrestis. — In my notes I find recorded the 

 following varieties : — 



