154 ANNALS NEW YORK ACADEMY OF SCIENCES 



This form is closely related to G. welleri, but differs in some particulars. 

 J. P. Smith figures two mature examples of G. welleri, and it is perhaps 

 desirable to distinguish between the type and the auxiliary specimen. The 

 type specimen of the variety gracile is a little more compressed than the 

 specimens of G. welleri, but I am not sure that the difference would be 

 constant. The venter also seems to be narrower and to show the channeled 

 condition at a stage when the type of G. welleri was rounded. The 

 sutures are more closely arranged than in Smith's second specimen, but 

 not more so than in his type. This feature is better shown in the former, 

 from which the detail was drawn, than in the latter. The sides of the 

 lobes and saddles are more sigmoidal as given by Smith. They are very 

 nearly a constant distance apart, whereas in the Wewoka form, they are 

 almost in contact at one point as described above, and the first lobe is 

 much narrower. These differences are not so marked in the case of the 

 type specimen, but there the point of the second lobe is nearly in contact 

 with the inner side of the lobe immediately preceding, an arrangment 

 quite different from the variety gracile. Furthermore, Smith definitely 

 states that the ventral saddle in his form is not notched, but has a tongue- 

 shaped forward extension, whereas the extension in my shell is as cer- 

 tainly backward. 



These differences appear to be rather constant for the material exam- 

 ined, and it seems unwarranted to consider the Wewoka form as quite 

 identical with the other. 



Horizon and locality : Wewoka formation ; Wewoka quadrangle, Coal- 

 gate quadrangle, Okla. 



Crustacea 



Griffithides parvulus sp. nov. 



Carapace small, elliptical, length about 2.5 times the width, nearly equally 

 divided between cephalon, thorax and pygidium. The head, however, even 

 without the genal angles, is longer than the pygidium. 



Cephalon semi-elliptical in shape, considerably wider than long (if the 

 width is measured from the anterior extremity to the edge of the neck ring), 

 rather tumid. Genal angles prolonged into spines of undetermined length. 

 A broad, striated border passes around the arc of the cephalic shield, ter- 

 minating posteriorly in the genal spines. The border is strongly arched or 

 subangular transversely, so that the outer surface is directed obliquely down- 

 ward and outward, and the inner surface obliquely downward and inward, 

 thus causing it to be denned from the inner parts of the cephalon by a deep 

 sulcus. Tbe sulcus dies down to a depressed line as it passes around the 

 front of the glabella, and at the same time the direction of the border be- 



