250 MYEIOZOIDJE. 



The direction in which the inaudible of the avicularium 

 points is also very variable in this species : most commonly 

 it is placed transversely; but very often it is turned straight 

 upwards, or obliquely downwards or outwards. 



The mucronate process, which is often present below 

 the mouth, is likewise subject to many diversities in the 

 degree of its development. In some cases it is absent 

 altogether ; in others it is small and inconspicuous ; in 

 others again (as in the var. crucifera) it rises into a tall 

 and slender spine, which gives off one or more branches. 

 In this form it is occasionally double ; the ovicell is 

 sometimes developed round one of the two spines, the 

 extremity of which appears as a spike-like process on the 

 front of it. In the Mediterranean variety (nitidd) the 

 mucro is large and massive, and traversed by radiating 

 ridges. 



The variety hastata presents some very striking features ; 

 and I at one time regarded it as a distinct species. The 

 tall mucronate processes, each with a rather large lateral 

 avicularium at the base, are profusely developed; the 

 orifice has a broad sinus on its inferior margin; the 

 zoarium is usually white and silvery ; and the surface is 

 covered with large punctures, which often assume a 

 radiated arrangement. The ooecium has not unfrequently 

 a mucro at the top. 



HABITAT. Under stones, near low-water mark, and on 

 shells, stones, &c., and more rarely on Algae, from shallow 

 to very deep water. 



LOCALITIES. Very abundant and generally distributed. 

 Shetland, common down to 170 fathoms. Var. crucifera : 

 On a shell dredged in 40-50 fathoms off Unst (A. M. N.) : 

 Orkney (Barlee) : Ireland, north and west (W. T.) : Bir- 

 terbuy Bay (G. S. Brady) : Beaufort Dyke, 110-147 

 fathoms (Capt. Beechey) : Filcy, Yorkshire, between tide- 



