REPORT OF THE DIRECTOR I9IO 207 



The two figures of plate 3 present views of different portions 

 of the area partly shown in plate 2, figure i. The broken inner 

 edges of the two rear hydrospires to the right of c are better 

 shown, and next to these is a hydrospire that still retains a por- 

 tion of its inner rounded edge. The suture between deltoid and 

 bibrachial is reproduced without retouching and the hydrospire exits 

 show their beautifully arched upper surfaces. The low^er figure 

 presents a region farther to the right, shows several interbrach- 

 ials with the still higher and larger hydrospire exit above them 

 and at / shows a single hydrospire sheet that was washed with 

 w^ater on its left face and bathed with coelomic fluid on its right. 

 The right side of this wall presents fine vertical lines which are 

 easily seen in the photograph and which it is hoped will be still 

 present in the reproduction. This appearance of corrugation in 

 the walls of the hydrospires was first noticed in a fragment now 

 in my possession and was mentioned in Bulletin 107, page 107. 

 This corrugation securing strength with extreme thinness (the 

 sheets in the figures of this plate represent secondary thicken- 

 ing that took place long after death) is also strongly indicative of 

 the function of respiration. 



If to the evidence here given we add that presented by the 

 cross section of a deltoid and two pseudambulacra, figured in 

 Bulletin 107, page 105, we must agree that we have as complete 

 a case as can be desired. In that section we found limonite- 

 colored muds in each and every one of the cavities through which 

 we maintained that there w^as a flow of water and these muds 

 were not detected in any other position save that of the intestine. 



These observations may serve to throw some light on the 

 Hambach-Carpenter controversy which T had not seen at the 

 time of making my first description of Blastoidocrinus (Bulle- 

 tin 107, 1907). I am greatly indebted to Mr Edwin Kirk for 

 recently loaning me these papers. There seems to be no doubt 

 but that we may accept the essential correctness of Hambach's 

 cross section of a Blastoid pseudambulacrum as shown in plate 

 2, figure 8 of his " Revision," with the exception that the pores 

 communicating with the hydrospires should open through the 

 membrane covering the floor of the extended food groove area. 

 Doctor Carpenter has stated 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 Echinoderms ' can have been preserved 



