REPORT OF THE DIRECTOR I919 85 



In the cross-sections of the conchs, both the dorsal and ventral 

 sides appear a little flatter or less curved than the lateral sides. 

 This, however, may be due to later compression. 



Another observation that to us seems to indicate a crawling habit 

 of this species has been made in specimens found in ihe Utica shale 

 at Holland Patent. These specimens are overgrown with a delicate 

 creeping bryozoan, Spatiopora lineata com pacta 

 nov. The zoaria of this bryozoan begin to grow near the apex and 

 then regrow forward toward the aperture and on one side of the 

 conch only. They would, of course, have also grown on one side 

 only, if they had spread over the conch while, after the death of the 

 creature, it was resting on and partly imbedded in the bottom mud. 

 It is, then, inexplicable why they should have grown forward as a 

 rule, upon the conchs ; a fact that clearly suggests that they attached 

 themselves to the living and still growing shells and grew with the 

 latter. In that case, the fact that the bryozoan shunned the under- 

 side would also indicate that this was a true ventral side in the 

 movements of the animals, and that these latter were upon the 

 bottom. 



Dr Rudolf Richter, in Frankfort a/M who has lately (1919) pub- 

 lished an excellent study of the coloring of fossil brachiopods has 

 upon my informing him of my find, kindly pointed out to me (in 

 letter of May 14, 1920) some questions that were raised in a dis- 

 cussion of my observation by his colleagues and that are liable to 

 be raised also by others and therefore may be answered here. These 

 are: 



1 Is the siphuncle somewhat excentric in that species ; and if so, 

 is the colored part of the shell oriented toward this excentricity of 

 the sipuncle? The siphuncle is visible only at the narrow end of 

 the second specimen and there is central in position. 



2 Can the loss of color on the single shell not have come about 

 postmortem? And then on the exposed side only, which was the 

 upper at the entombment of the shell, while the side lying in the 

 mud favored the preservation of the colors as much as in many Ger- 

 man ceratites the longer preservation of the conch on the underside 

 (cf . Phillippi und Riedel : Beitr. z. Pal. u. Strat. d. Ceratiten ; Jahrb. 

 Preuss. geol. Landesanstalt 1916, Bd. 37, Teil i, Heft, i) ; or like 

 the mummy of Trachodon has preserved its skin only on the (pre- 

 sumed) underside? 



Dr Richter adds in his letter that my observation of the wider 

 spacing of the bands toward the lateral sides indicates a primary 

 differentiation in the coloring of both sides of the conch. Also the 



