[NVBRTEBEATE PALAEONTOLOGY. 405 



My friend Mr. Grabb, finding the septa of B. asp&r corresponding rather 

 nearly with those of B. anceps, Lamarck, adopted the conclusion that these 

 forms are really only varieties of one species. To me, however, it seems 

 that Ihe more gibbous form and more rounded siphonal side of B. asper, 

 together with its rows of node-like prominences, instead of curved undula- 

 tions or ridges, ought to separate it from B. anceps. A considerable time 

 and attention devoted to the study of specific differences in this genus has 

 led me to the conclusion that we cannot always rely upon the septa alone, 

 in separating species, but that we must also take into consideration external 

 characters of size, form, ornamentation, &c. For instance, if we unite B. 

 asper and B. anceps, on account of the similarity of the septa, without regard 

 to other characters, I cannot see how we can avoid also including B. ovatus, 

 and the gigantic B. grandis, in the same species. I can agree with Mr. 

 Gabb, however, in the opinion that B. carinatus, Morton, is almost certainly 

 not distinct from B. anceps, Lamarck. 



Dr. Roemer has (in his Kreidebildungen von Texas, pi. ii, figs. 2, a, b, 

 c, d) illustrated a small Baculites that he refers to B. asper, Morton, which 

 seems to me hardly identical with Morton's species. At least, it differs in 

 having short, curved, angular prominences along each side, instead of rounded 

 nodes. He does not figure the septa, however, so we have not the means of 

 making comparisons of internal characters. 



The little fragment represented by figures 10 b, c, of our plate 3 ( J, was 

 at first thought possibly to belong to the same species as that from which 

 the drawings 10, a, d, were made; but I can scarcely doubt now that it rep- 

 resents a distinct species, its strong, oblique, nearly straight ridges or undu- 

 lations, extending entirely across the sides, being a very marked feature, 

 contrasting strongly with the node-like prominences on the other specimen 

 represented by figures 10, a, d. Although I have here referred the latter 

 provisionally to B. asper, Morton, its identity with that species is still an 

 unsettled question, and it may yet have to be separated under another name. 

 In that case, I would beg leave to substitute the name B. asperiformis for it, 

 instead of B. asperoides, which was inconsiderately used in a list only, with- 

 out a description, and is objectionable in construction. 



Locality and position. — Near the mouth of Judith River, Montana; in 

 beds holding a position near the top of the Fox Hills group of the Upper 

 Missouri Cretaceous series. 



