AND ITS ALLIES. 221 



coating which frequently characterises P. macrostyla^said more 

 rarely the type and some varieties of P. aculeata. 



Frequent, among moss, in the highlands of Scotland, from 

 Loch Morar to Shetland. 



11 Spines. 



The form described by Gosse has eleven spines. As Gosse 

 states that in the contracted state the last pair of spines 

 appears to terminate the body, it is probably the 5th pair which 

 is lacking in this form. 



Weber's 11-spined form has the 5th pair of spines, but lacks 

 the lateral spines. This form I have not seen. 



Certain authors have supposed that the lateral spines, which 

 at times stand out vertically to the surface of the trunk, or point 

 forward, may be laid down backward like the other spines, but I 

 believe this to be an error, and that when they disappear as 

 the animal creeps, they are laid down forward between the 

 skinfolds. 



10 Spines. 



Variety. — The five pairs of spines are the 1st, 2nd, 3rd, 5th, 

 and 6th. The lateral pair of spines is present ; the absent pair 

 is the sublateral 4th pair (Fig. 12). The 1st pair is reduced to 

 rounded knobs. The 2nd pair is longest of all, as in the type. 

 Near Glasgow. 



Variety. — The five pairs of spines are the 1st, 2nd, 4th, 5th, 

 and 6th. The forward-pointing lateral spines alone are lacking. 

 The second pair are longest (Fig. 23). 



Variety. — The spines are, as in the preceding variety, pairs 

 1, 2, 4, 5, and 6. The 1st and 2nd pairs have reversed positions 

 as to size, the 1st being very large and strong, while the 2nd are 

 the shortest of all. 



8 Spines. 



I have seen no form, having less than eight spines, which 

 possessed the lateral pair of spines, directed forward. Mr. 

 Milne's variety has this pair; so far as can be judged from 

 his very slight figures, the spines are the 1st, 2nd, 3rd, and 4th ; 

 the 5th and 6th absent. 



