406 NEW YORK STATE MUSEUM 
Hastimima whitei, and it is probable that this generic term will 
have an independent value, for though the telson in its outline is certainly 
comparable to that of certain species of Pterygotus,as P. minor Wood- 
ward, its section is totally different from that of any of the Pterygotidae 
and the fragment of segment indicates a different inclination of the side 
of the body than is observable among other pterygotids. 
Note on Sidneyia inexpectans Walcott 
Among the remarkable remains which have been described by Dr 
C. D. Walcott from the Cambric is a wonderful arthropod Sidneyia 
inexpectans, which has been brought to public notice just as this 
work is completed.' 
This organism is extraordinary in the preservation of its anatomy and 
as both it and its associate, Amiella ornata, are referred by Dr 
‘Walcott to the Merostomalta, they invite brief notice in this place. Both 
are from the Middle Cambric (Stephen formation) of British Columbia. 
Amiella ornata 1s based on a fragmentary portion of an abdo- 
men and for this reason will not be included in our annotations. These 
refer entirely to the splendid material secured of the species Sidneyia 
inexpectans. : | 
Sidneyia and Amiella are united in a new suborder Limulava 
of the Eurypterida. | 
The suborder is described as follows: 
Body elongated with a thin epidermal skeleton either smooth or orna- 
mented by lines or ridges. Cephalothorax with lateral or marginal eyes, 
on the ventral side with five pairs of movable appendages, mouth posterior 
to a large epistoma. 
Abdomen with twelve segments, the anterior nine of which have a pair 
of ventral appendages to which the branchiae are attached; the posterior 
segment has a central spatulate-shaped section that, combined with swim- 
merets, forms a strong caudal fin. 
1C, D. Walcott. Middle Cambrian Merostomata. smithsonian Miscellaneous Collec- 
tions. I91I. Vv. 57,noO 2. p. 15. 
