Miss Agnes Crane — Evolution of the Brachiopoda. 67 



The living forms are universally distributed in the seas of the 

 world. Their range in depth is no less extended. They occur in 

 shallow waters, at low water-mark, and varying degrees of depth, 

 from 200 to 600 fathoms being the usual limit of the majority of 

 species. Several far-ranging abyssal species were dredged in from 

 1000 to 2000 fathoms. The delicate transparent shell of that 

 intei'esting little Terebratuloid Liothyrina (Terebratula) Wyvillei, 

 Dav., was actually obtained in a living condition by the "Challenger" 

 Expedition from the enormous depth of 2900 fathoms, or three 

 miles and a quarter, at the bottom of the South Atlantic Ocean (30). 



Such manifest adaptability to varied environments is probably one 

 of the main causes of the persistence of the group throughout the 

 geological ages. The Brachiopoda seem to flourish alike in tropical 

 seas and the frigid abysses of the ocean. They are extremely 

 tenacious of life in captivity, pursuing — 



" The noiseless tenour of their way " 



for months and even years together. An occasional yawn seems to 

 be their only diversion. The animals are, however, sensible to light 

 and close their valves abruptly on the interposition of any shadow. 

 The "gape " is less than in the oyster. Civilized man who swallows 

 that succulent, but often insanitary, bivalve, is apt to draw the 

 gastronomical line at the Brachiopod, but in the Philippine Islands 

 where Lingulas abound and are cast up by the sea, like mussels on 

 our shores, the natives collect them for food. It is evident from 

 the small space alloted to the animal in some of the fossil species 

 that there was very little to eat in them. Many fishes are ardent, 

 if somewhat indiscriminating, " collectors " of Brachiopods. One 

 would imagine the spinose forms would prove rather indigestible ; 

 but the contemporary sharks and other fishes were furnished with 

 powerful crushing teeth, and doubtless made "small bones" of 

 those ornamental appendages. 



The use of these spines, so extensively developed in adult 

 individuals of several families, is not actually determined. In 

 some species they were evidently flexible, and served as moorings 

 or as clasping organs, as in the case of that little Productoid which 

 Fischer and (Ehlert re-named Etheridgina in honour of its first 

 describer, for this Productus complectens clasped its spines round 

 the stems of the sea lilies, swaying to and fro in the ocean's depths. 

 In other forms they were tubular, and Dr. John Young has described 

 species with double spines, one contained within the other (74). 

 Such may have subserved the function of respiration, or to admit 

 water to the interior of the shell preventing the introduction of 

 impurities, as De Verneuil had previously maintained. The spines 

 obviously afforded no protection to the species in the struggle for 

 existen ;e, for only one spinose form survives out of many members 

 of various families thus ornamented. This interesting example is 

 that of the little living Khynchonelloid which was dredged by 

 Doderlein in Sagami Bay, Japan, and was named E. Doderleini by 

 Davidson just before his death (31). This curious survival belongs 



