338 NEW YORK STATE MUSEUM 



wall of the distal parts very convex, in the thecae of the biserial portion 

 (and perhaps also in the others) furnished with short mesial spines. 

 The apertural part strongly introverted and introtorted ; contained in a 

 deeply curved excavation which occupies about two fifths the width of 

 the branch. 



Position and localities. A small slab of Normanskill shale from Ken- 

 wood, N. Y. was found to be covered with specimens of D . contort us, 

 in association with Crypto g r. tricornis. A few specimens were also 

 found in the same formation at Mt Olympus in Troy, associated with 

 C 1 i m a c o g r. parvus. 1 



Remarks. This most curious form has in the compressed state all 

 the appearance of much segmented worms which have coiled before death 

 and only the spinose biserial portions which here and there connect the 

 pairs of enrolled branches indicate the true nature of the fossil, naturally 

 surmised from the association and strong periderm. The branches were 

 evidently round in section, furnished with strong periderm and originally 

 like the other Dicranograpti coiled into oppositely directed spirals which 

 seem to have been short and compact. The contortions are clearly of post- 

 mortem origin, and resulting from the wiry character of the branches. 



There has been no species of Dicranograptus described with which 

 this one could be confused ; it differs from all by its small size, contorted 

 branches and close arrangement of thecae, but it is clearly a diminutive 

 member of the group hitherto represented by D. furcatus Hall and 

 D. ziczac Lapw., characterized by extreme spirality of the branches, 

 highly convex ventral walls of the short thecae, strongly introverted 

 and introtorted apertural parts and more or less spinosity of the thecae. 

 In all these characters the paracmic condition of the genus becomes 

 apparent. 



1 The writer has also observed a characteristic specimen on a slab from the western 

 graptolite shale, but having failed to properly mark it at the time of the discovery, has not 

 been able to find it again. 



