162 REPORT — 1861. 



crisped and twisted ; fronds sometimes temiinating in crispy furcations. Gathered 

 in North Wales. 



Blechnum S. trinerviuyn (Moore). Nearly the size of the species, characterized 

 by the lowest pair of lobes being developed into miniature fronds. Found in Ire- 

 land. 



Blechnum S. multifurcatum (Moore). Distinguished by the fronds, both barren 

 and fertile, being variously branched and furcate at the ends. Gathered near Tod- 

 morden, in Rossendale, and other places. 



The forms previously mentioned are all distinct from one another, and are beau- 

 tiful and interesting objects, either for pot culture or fern houses, for Wardian 

 cases or rockwork in the hardy fernery. 



The following varieties (many of them gathered during the past season) I have 

 submitted to Mr. Moore, who considers them quite distinct and permanent forms, 

 and has named them accordingly. Most of them are exceedingly interesting, but 

 my acquaintance with them is not sufficiently extended to enable me to vouch for 

 their pennanency. 



Blechnum S. serratum. 

 repanduna. 



mundulimi. 



apiculatimi. 



aberrans. 



poiTectimi. 



pauperculimi. 



imparatum. 



minimum. 



Blechnum S. variegatmn. 



cnstatum. 



• deficiens. 



• fiu'catmu. 

 subcrenatum. 

 tridactylimi. 



■ prremorsum. 



■ dentigerum. 



• abniptum. 



Observations on the Development of Sjiiapta inhserens. 

 By Professor Wtville Thomsoj^, LL.D. 



On some Points of Interest in the Structure and Habits of Sliders. 

 By TuFFEN West, F.L.S. 

 The object of this paper was stated to be, rather to dissipate erroneoiis opinions 

 commonly held, by the mention of facts, than to set forth novelties j and by 

 adverting to some of the many points of interest in the structure and habits of 

 spiders, to lead to their being regarded with better feelings, and perhaps more 

 attended to by students of Natural History. A more favourable opportimity could 

 not present itself than such an occasion, when those who professedly study science 

 are met and listened to by the intellectual and the highly cultivated, with whom rests 

 the privilege of giving to the age its prevailing tone of thought. The colouring of 

 spiders is seldom other than rich in its tones ; in making figures of them great dif- 

 ficulty is experienced in getting colom's of sufficient brightness. That there is an 

 adaptation of the general tone of colouring to the places inhabited by difierent 

 spiders is certain ; how far individuals that have arrived at niatmity may be able 

 on changing their abode to modify their colours is not known, though it is probable, 

 from the great variety readily observable in this respect, that during growth at any 

 rate there may be some such adaptive power. The alterations in colour of the 

 anterior pair of eyes in some spiders, from ruby-red or emerald-green to golden- 

 yellow, by a perceptible internal motion, are very remarkable, and the means by 

 which such change is effected deserve careful study. In the instincts of spiders 

 there is much to interest. The intimate structure of the web of the Diadem- 

 spiders is known to most as a favourite microscopic object ; the radii in this web 

 are cords ser\'ing principally for the support of the highly elastic spiral line, with 

 its drops of viscid material. In the Ciniflonidaj none of the lines forming the 

 snare are viscid, but insects are quite as eftectually entangled by a pair of tine 

 double lines, so disposed along a framework as to form very numerous double loops. 

 The apparatus employed in the construction of these loops is composed of a double 

 row of spines on the metatarsus of each hind-leg. Some of the tent-forming 

 spiders iu fine weather make their covering of a very slight texture, but in wet 



