ON NEW BRACIIIOPODA, 161 



lamellte are still attached to its npper sldes, and the 

 reflected portion of the loop lias become fully developed, 

 the extremities facing the front of the shell being consider- 

 ably prolonged, as is seen in fig. 5 of our plate. Numerous 

 long spines also project from the outer edges of the lamellte 

 and loop, giving to the interior a very peculiar appearance. 



The subject of the development of the internal calcified 

 Supports in brachiopoda is of considerable interest, and 

 much may yet be learnt by a careful study of recent 

 specimens of this class. The importance of attention to 

 the subject is the greater Avhen it is remembered that tlie 

 Classification of many of the brachiopoda depends more 

 lipon internal than external form, and that had the different 

 stages of development shown by the Terehratella Buckmanii 

 been observed under other circumstances, or from beds of 

 different geological ages, each would probably have been 

 constituted a distinct genus. 



The Terehratella Buckmanii is the prevailing shell at 

 Hampton Cliffs, and many hundred specimens have passed 

 through my hands. It has before been remarked that the 

 young of Terehratula maxillata also occur at Hampton, 

 though this species is comparativcly rare. It requires con- 

 siderable experience to determine by the exterior to which 

 genus the different shells belong. Both possess the same 

 contour, and are strongly punctuate. In general, however, 

 •the Terehratella Buchnanü may be distinguished by a dark 

 longltudinal line in the centre of the ventral valve, due to 

 the mesial septum, and by the characters previously noticed 

 Avhen spcaking of Terehratula maxillata. 



It is due to my friend Mr. Woodward I should remark, 

 that whilst my invcstigations on this shell Avcre in progress, 

 having bccn the mcans of conveying a serics of them to 

 him, he noticed it to be a Terehratella; and in a communi- 



VOL. X., 1860, PART II. w 



