137 



Kansana n. n. (S. undulata Lesq.,* not of Pohlf), from the 

 Dakota group in Kansas. 



Tithymalus phenacodorum sp. nov. 



Seed. Length 4.75, breadth 4.25 mm.; short-pyriform, with 

 four sides sHghtly flattened; surface coarsely irregularly wrinkled. 



Five miles southeast of mouth of Pat O'Hara Cr-eek, Clark's 

 Fork Basin, Wyoming; above red-banded beds, in strata sup- 

 posed to be older than the Wasatch, though formerly classed 



A. 



Fig. 2. Seeds of Tithymilus: A. T. phenacodorum, side view. B. T. phenaco- 

 dorum, from above. C. T. Willistoni, side view. 



with that group. Type in American Museum of Natural History ; 

 collected by Mr. W. Stein, along with numerous remarkable land 

 shells, of the genera Protohoysia, Boysia, Vitrea, Thysanophora, 

 Pyramidula, Gastrodonta and Oreohelix. 



Compared with the seeds of T. Willistoni Cockerell,; from the 

 Loup Fork Beds of Long L, Kansas, the new species is distinctly 

 longer, while the depressions between the rugse are more irregular 

 and less definitely in longitudinal series. A quite similar but 

 still longer seed is that of the living Mexican Tithymalus 

 campestris n. n. (Euphorbia campestris Cham. &Schl., 1830), the 

 seed of which is well figured by Millspaugh, Botanical Gazette, 

 XXV (1898): 25. In T. campestris, however, the rugae are 

 more labyrinthiform than in T. phenacodorum. 



Extremely hard and dense seeds, such as those of Tithymalus, 

 are readily fossilized where ordinary vegetation decays and 

 disappears. It is probable that careful search will reveal them 

 in other Tertiary strata. I add a figure of T. Willistoni, as it has 

 not been figured. 



* Fl. Dakota Group: 39 (1892). 



t Pohl, A. DC. in D. C, Mon. Phan. i: 135. 



JTorreyag: 119. 1909. 



