208 MICROPORELLID^. 



form. Spines : variable in number, and often wanting 

 altogether, especially in deep-water specimens. In a re- 

 markable Australian form tliey are dark-coloured at the 

 base, as in Cribrilina Gatty(B. Median pore : sometimes 

 nearer to the lower margin of the orifice, sometimes more 

 remote ; often elevated on a mucro or knob ; in the hooded 

 variety inclosed by the wall-like extension of the ooecium. 

 Avicularium developed indifferently on either side of the 

 cell, and rarely on both sides : mandible in many cases 

 extended into a vibraculoid process. Ooecium : simply 

 globose or hooded, areolated or plain; sometimes with a 

 prominent umbo on the front of it. 



Habitat. On the red weeds (the delicate variety) , stems 

 of Laminaria, shells of limpet in rock-pools, stones and 

 dead shells &c., from between tide-marks to 300 fathoms. 



Localities. Generally distributed round our coasts. 

 Shetland, tide-marks to 90 fms. (A. M. N.) : off the Dead- 

 man, Cornwall, 60 fms. (T. H.) : Beaufort Dyke, 110-145 

 fms. (Capt. Beechey) : Belfast Bay (W. T.) : Dublin Bay 

 (A. H. H.). \Qx.personata : Hastings (Miss Jelly) : Corn- 

 wall; Isle of Man (T. H.) : Birterbuy Bay (Norman) : &c. 



Gkographical Distribution. Cosmopolitan. Spitzber- 

 gen, 6-30 fms. (Loven) : Greenland (Liitken) : Nova 

 Zembla, 15 fms. (Nordenskiold) : Bahusia, in deep water 

 (Smitt) : coast of Norway, 300 fms. (Sars) : coast of 

 Florida, 7-60 fms., hooded variety as well as the normal 

 form (Pourtales) : Roscoff, common, especially on Chon- 

 drus (Joliet) : Naples, common, down to 40 fms, (A. 

 W. Waters) : Adriatic (Heller) : Algiers (J. Y. J.) : East 

 Falkland Islands, 4-10 fms,, var. personata, Busk (Dar- 

 win) : Geelong ; New Zealand, in Pectunculus (T. H.) : 

 Zanzibar; Aden; Arabian Sea, on weed, taken up in lat. 

 about 15° N., long, about 65° E. (W. Gates) : attached to 

 the Falmouth and Lisbon cable, between N. lat, 47° 58' 



