76 EDITH M. PRATT, B.SC. 



in Italiau pliocene, Austrian miocene, and tertiary formations at 

 Reggio (Italy). The distribution of this species gives evidence in 

 support of Murray's view. 



Membranipora. The genus is cosmopolitan, chiefly in shallow water, 

 but it also occurs in deep water. 



M. albida, Tongatabu (Pacific), 21°S., 18-20 fath. Bermuda, 

 38° 37'N., 450 fath. Singapore. 



M. crassimarginata, Bass Strait, 38-85 fath. Heard Island, 75 fath. 

 Tristran D'Acunha, 1 10-150 fath. Gulf of Florida, 13-60 fath. 



M. multifield, Cape of Good Hope, 450 fath. Challenger station 320, 

 37° 17'S., 600 fath., green mud. 



It is notable that the species occurring at great depths are found only 

 in temperate regions. The tropical forms occur in fairly shallow water. 



Membranipora membranacea occurs in north and south temperate 

 zones, but not within the tropics. 



M icropora. Genus extends back at least to the chalk period. It 

 occurs in north and south temperate zones, as well as the tropics, in 

 shallow to fairly deep water (greatest depth recorded, 150 fathoms). 

 The species M.uncifera is recorded only from the southern hemisphere. 



Microporella. Genus cosmopolitan. 



Microporella ciliata is also cosmopolitan ; the specimens taken at 

 greatest depths have been limited to temperate regions, namely : 

 Bahusia, on the Falmouth and Lisbon cable. 47° N., 89-205 fath. ; and 

 the coast of Norway, 300 fath. The tropical specimens occur in fairly 

 shallow water. 



The species M. malusii occurs north and south of, but not within, the 

 tropics in fairly shallow water (10-50 fath.). It occurs fossil ; coralline 

 crag, older pliocene (Castrocaro). 



Mticronella. The genus is cosmopolitan, from fairly deep water, but 

 the species M. tricuspis appears to be restricted to the southern 

 hemisphere, from shallow to fairly deep water, 12-150 fath. Fossil — 

 tertiary — New Zealand, The species occurring at the greatest depths 

 occur also in temperate regions, with one exception — Challenger 

 Station 122, off East coast of South America, 9° 5' S. ; the species 

 M. castanea occurs from 32-100 fath., and, with this exception, all other 

 tropical species occur in fairly shallow water. Many of the species of 

 this genus are fossil, occurring in coralline crag, middle pliocene, upper 

 pliocene, palaeolithic, Scottish glacial deposits, &c. 



