774 REPOKT 18'J2. 



tliin neck of the spine soon widens out into a liemispberical root, the convex in- 

 ternal aspect of which is indented by a small vascular papilla. The sheath of 

 this root consists of epidermic and of dermic coverings ; of the latter nothing need 

 he said ; the former presents two layers, an outer and an inner root sheath, which is 

 not subdivided into several layers of cells. A large fan-shaped arrector pili 

 muscle is attached to the dermic coverings ; it consists of non-striped fibres firmly 

 attached, for the most part, to the deeper layers of the rete mucosum. In the 

 neighbourhood of the spine is a fine capillary plexus ; there appear to be no special 

 nerve end organs, though tactile impulses are conveyed in some way from the 

 spines to the brain. 



The ventral region gradually passes into the dorsal at the sides of the animal. 

 The skin is much thinner, less rugose, and less firml}' attached to subjacent 

 structures than that of the dorsum ; it is covered with hair, and contains both 

 sweat and sebaceous glands. 



The epithelium is similar to that of the dorsum. 



The cutis vera is thinner and finer than that of back, very vascular, and 

 contains much adipose tissue. 



The panniculus carnosus of striped muscle is thin, and exhibits some fibres in 

 a more or less embryonic condition. 



The sweat glands, situated deeply in the cutis vera, are lined by a single layer 

 of cells surrounding a central lumen ; the non-striped muscle fibres between them 

 and the basement membrane are inconspicuous or wanting. The ducts are lined 

 by a single layer of cells. 



The hair follicles are similar to those of other animals ; the arrector pili muscle 

 and sebaceous glands are large. 



Hairs and Spines. — The hairs are of the fibrous or fibro-cellular type, depend- 

 ing on their size; they exhibit a cuticle, a cortex, and a medulla. There is a gradual 

 transition between the soft hairs and ridged spines at the sides of the animal. 



The spines are gigantic, somewhat modified hairs, consisting of a cuticle, a 

 cortex, and a medulla. 



The cuticle is a single layer of large imbricated scales. 



The cortex is fibrous in appearance, contains pigment at intervals, and is 

 strengthened internally by twenty-two to twenty-iour longitudinal ridges that 

 project inwards for some distance into the medulla. 



The medulla is of large size, thickest in the middle of the shaft, tapering 

 towards the tip and neck of the spine ; it is divided into narrow lenticular 

 chambers by transverse imperforate septa, each of which splits horizontally at 

 the margin into several leaflets, which in their turn again split horizontally into 

 still smaller leaflets ; all the leaflets are firmly attached to the sides of the inward 

 projecting cortical ridges, thereby firmly binding them together and helping them 

 to withstand a vertical strain, the septa themselves preventing undue distortion of 

 the spine from a transversely applied strain. Morphologically the spines are true 

 hairs. 



10. On the Industry and Intelligence of Insects in relation to Flovjers, 

 Bij Rev. Alex. S. Wilson. 



TUESDAY, AUGUST 9. 

 The following Papers were read : — 



Department of Botany. 



1. Tubercles on the Thallus of some Floridece. 

 By Professor' Schmitz, of Greifswald. 



