Report of the State (1 rolooist 



459 



also mentions a species of Chonetes apparently attached by 

 the spines on the cardinal margin, but this observation seems 

 to require verification. Prod/ucteUa na/oicella, of the Devonian, 

 has the spines in the umbon; 1 1 region of the large valve curved 

 upward, those from opposite sides passing each other; like a 

 man's arms extended and folded above his head. These were 

 undoubtedly clasping or anchoring spines. 



It is even possible that fixation by mooring, or temporary 

 attachment was effected by an extravagant growth and enfolding 

 of the anterior portions of the larger valve, in some Carboniferous 

 productoids (Proboscidella) which have been described by De 

 Verneuil, De Koninck, Davidson and others. 



Fig. 7.— Ether idgina complectens attached by 

 its spines to a crinoid column. (Etheridge.) 



Fig. 8.— Productella navicella, showing the 

 clasping spines in the umbonal region. Hamil- 

 ton group; New York. 



The capability of locomotion in the brachiopods was very 

 limited. During the unattached condition the spawn were active 

 swimmers. Terebratulina becomes attached very early in its 

 history, while Discinsca is fixed only after many of the adult 

 characters have been assumed. It is difficult to believe that any 

 power of locomotion was possessed by the ancient forms in which 

 the pedicle was atrophied at maturity and the shell thus set free, 

 as Spirifer, Productus, some forms of Athyris, etc.; or that the 

 animals could depend on other than circumstantial causes for a 

 change of place. Some writers have suggested that the long- 

 spines with which several genera, especially Productus, are 

 furnished, may have been aids to such motion, but as these spines 

 were unquestionably rigid bodies, it is difficult to believe that they 

 could have had any part in the voluntary motion of the animal. 



Distribution. The brachipods are gregarious in habit and over 



a given area of the sea-bottom a single species will frequently be 



found in great numbers. " Prof. Jukes got immense numbers of 



Waldheimia jlavescens or australis while boating in Australia 



11 



