460 Forty- fifth Report on the State Museum. 



among the reefs. M. Velain picked up a small species of Krajts- 

 sina in vast numbers on the shore in the interior crater of the 

 island of St. Paul, the shells being alternately covered with water 

 and left dry at every tide. Kraussina rubra, from the coast of 

 Natal in South Africa, was described by Dr. Gray as having been 

 found attached in great numbers to Ascidia and stems of sea- 

 weeds" (Davidson). It is said that more than twenty bushels of 

 Lingula omatina were picked up after a violent storm on the 

 coast of Manilla, and CEhlert states that on the coast near 

 Guernsey were found at one time about two hundred specimens 

 of Cistella cistellula. 



Some of the genera and species of brachiopods possess remark- 

 able power of resistance to physical conditions, and are found at 

 various depths. The genus Discinisca has representatives within 

 five fathoms of the surface and at a depth of 2,500 fathoms ; the 

 species Terebratulina eaput-serpentis ranges from near the surface 

 to a depth of 1,195 fathoms. The greatest depth from which any 

 species has been dredged is 2,945 fathoms {Liothyrina Wyvillii). 



The evidence afforded by living species is as yet insufficient to 

 determine the effects of bathymetric conditions upon specific 

 characters. It is evident that different species are variously 

 affected or inequably resistant to these influences ; but as a general 

 rule, different species or associations of species are found at differ- 

 ent depths. 



In the summary of bathymetric distribution of living species as 

 given by CEhlert, it appears that in the Littoral Zone, or that 

 between tides, there are 17 known species, 7 of which are peculiar 

 to it ; in the Laminarian Zone (to a depth of 15 fathoms), there 

 are 46 species, 15 of which are peculiar to it ; in the Zone of Nul- 

 lipores (from 15 to 50 fathoms) are 39 species, of which but 3 

 are restricted to it; in the Zone of Brachiopods (from 50 to 

 278 fathoms), 58 species have been found, and 20 of these 

 are not known elsewhere ; in the Abyssal Zone (from 278 to 2.945 

 fathoms) have been found 30 species, of which 12 do not 

 occur elsewhere. It is, however, to be observed that in those 

 conventional divisions the so-called restricted species occur either 

 in zones of great vertical extent or those whore organic lite gen- 

 erally is the most prolific. There is no evidence thai this bathy- 

 metric range of the brachiopods has been effected by any other 



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