398 UNITED STATES GEOLOGICAL SURVEY OF THE TERRITORIES. 



B :i c n B i t e s grandis, H. & M. 



Plate 3:!, figs. 1, a, h, c, ami annexed ruts. 



BaculUen grandis, Hall and Meek (1854), Mem. Am. Acad. Arts and Sci. Boston, V (n. a.), 402, pi. vii, figs. 

 1 and -2: pi. viii, figs. 1 and -2; and pi. vi. fig. 10.— Gabb (18(11), Synop. Moll. Cret. 

 Form.. -21.— Meek (1864), Smithsonian Check-List N. Am. Cret. Fossils, 23. 



The form represented by the figures on our plate 33 is only known by 

 the specimen there figured, and is merely referred very doubtfully to B. 

 grandis. l\' it belongs to that species or variety at all, it of course must 

 either be a part of a small specimen, or a fragment from below the undu- 

 lated part of a large one. It presents an ovate section, with a convexity 

 equaling about two-thirds its greater diameter. It is not quite so obtuse on 

 the siphonal side, nor so flattened on the antisiplional surface, as the corre- 

 sponding part of the septate portion of the typical B. grandis. Like this 

 part of both B. grandis and B. ovatus, it is entirely without lateral undulations ; 

 while in the characters of its septa, it will be seen from our figure to be about 

 intermediate between those two forms ; the differences from each being rather 

 in minor details. The terminal branches of its lateral lobes, however, are more 

 like those of B. grandis, but its antisiphonal lobe, and some of the details of 

 the others, are more nearly as in B. ovatus. As the published figure of a 

 septum of B. grandis was made out, however, from a somewhat weathered 

 cast, composed of coarse material, the details of its lobes and sinuses may not 

 have been very exactly determined, particularly the form of its antisiphonal 

 lobe, which was only obscurely seen in the type-specimen. 



From the intermediate characters of the specimen figured on our plate 

 33, between B. ovatus and B. grandis, I am in doubt in regard to which of 

 these forms it should be referred ; and the existence of such a type raises the 

 question whether even the type-specimens of B. grandis may not really be 

 very large examples of B. ovatus. To any person onh familiar with speci- 

 mens of Say's species of small and medium sizes, such as are usually seen, this 

 suggestion will undoubtedly appear very improbable. Yet, with the large 

 collection of specimens now before me, of all sizes, from the very young up 

 to individuals nearly as large as the largest type-specimen of B. grandis, all 

 apparently inseparable from B. ovatus, the improbability of the specific 

 identity of these two forms is not so striking as might be supposed ; though I 

 am not contending that this can be clearly established from the collections 

 yet known. 



