-'sr. 



NEW YORK STATE MUSEUM 



The Plattsburg, X. Y.. specimens of S. em in on si whose an- 

 alyses were pubHshed in the report ah-eady cited, had but three plates 



Fig. 36 Analysis of Sigmacystis emmonsi Hudson, specimen D. The specimen found 

 by E. Billings near St Michel in 1857. The plates are numbered to correspond with the 

 analyses already published and the more prominent mounds and ridges are indicated by 

 hachures. The four oral plates and portions of plates 14. 15. 23 and 28 are from a photo- 

 micrograph and are used to illustrate the character of the sigma. The pits occupied by 

 the proximal brachiolar ossicles have had their approximate outlines dotted. There seems 

 to have been but four of the latter bordering each main food groove. The genital pore and 

 madreporite are indicated by hachures. The anal covering plates are also from a photomi- 

 crograph. All sutural lines on the photographic portions of figure have been intensified. 



in their first (aljoral) circlet. Two of these, however, appear to be 

 double plates, the l.ant.IR alone remaining single. In the St 

 Michel specimen the l.post.IR and the post. I R seem to have been 



