292 Dr. P. H. Carpenter on the 



ia not the one usually adopted by systematic zoologists, who 

 are generally careful to obtain the fullest possible knowledge 

 of a species before committing themselves to a positive state- 

 ment about its generic affinities. 



Mr. Hambach's morphological doctrines are equally open 

 to criticism. In his former paper * he gave an entirely new 

 interpretation of those limestone plates at the sides of the 

 ambulacra of Pentremites which Romer designated as sup- 

 plemental pore-pieces ; for they are " the remnants of collapsed 

 tentacles preserved in the poral openings." Further on, again, 

 he speaks of " the poral fissure from whence the tentacles 

 originate, leaving the interior of the calyx through the poral 

 openings, and forming in their collapsed state the supplemen- 

 tary poral plates of Dr. Romer." 



Mr. Hambach describes these statements as " the results 

 of my observations "f. Most readers would prefer to regard 

 them as expressions of individual opinion ; for he cannot pos- 

 sibly have observed the supposed tentacles of a living Blastoid 

 and the form which they assume when collapsed. Under 

 these circumstances I ventured to remark J that Mr. Hambach 

 " must have a wonderful power of imagination ; for he 

 actually believes that ' soft and membranaceous organs, such as 

 occupy the pores of the ambulacral field in JEchinoderms ' can 

 have been preserved (in a collapsed state, it is true) through 

 all the ages between the Carboniferous period and the present 

 time." 



His reply § was as follows : — " The shape in which these 

 hydrospiric plicas are found, as well as the difference in colour 

 between them and the adjoining opaque calcareous substance 

 of the shell, together with the physiological function ascribed 

 to them (respiratory, according to Billings), denote the once 

 elastic nature of these organs as well as of the tentacles, which 

 communicate with the hydrospiric sac through the poral 

 openings They form in their collapsed state the sup- 

 plementary poral plates of Romer, which, to the great 

 surprise of Mr. Carpenter, are actually found preserved in an 

 open condition from the Carboniferous period to the present 

 time." 



These assertions are of such an absolutely positive nature 

 that one is naturally led to ask, what possible proofs of them 

 can be offered by Mr. Hambach besides his statement that 

 " the interior circumference of a poral opening is lined by 



* Trans. St. Louis. Acad. vol. iv. p. 151. f Ibid. p. 537. 



\ ' Annals,' sev. 5, vol. viii. p. 423. 



§ Trans. St. Louis Acad. vol. iv. p. 539. 



