335 



TuRRiTOMA CONSTEICTA (Whiteaves). 



Murchisonia coMtricta, Whiteivves 1884. This volume, pt. I, p. 25, pi. 4, fig. 



4 ; and (1805) pt. II, p. 82. 

 rurWtoma consiricto, Ulrich and Soofield .. 1897. Geol. and Nat. Hiat. Surv. Minn., 



Final Rep., vol. Ill, pt. II, p. 959, 



Murchisonia Billinosana, Miller. 



Murchisonia Hercyna, Billings 18C2. Geol. Surv. Canada, Palseoz. Toss. 



vol. I, p. 158, fig. 141; but not M. 

 Hercyna, Roemer, 1843. 



Murchisonia billingmna, S. A. Miller 1889. N. Amer. Geol. and PaliEOnc, p. 411. 



The best specimens in the Museum of the Survey are the type specimen 

 of M. Hercyna figured by E. Billings, which he collected at Gait in 1857, 

 and a slightly smaller one from Elora, collected by Mr. T. C. Weston in 

 1867. These are the only specimens known to the writer upon which 

 any portion of the test is preserved. Both of them have recently been 

 examined by Dr. Ulrich, who writes as follows in regard to them, in a 

 letter dated April 7, 1906. " As is proved beyond the shadow of a 

 doubt by the peripheral portion of the smaller specimen, this is not a 

 Murchisonia, nor even one of the Pleurotomariidse. It is no less certain 

 that it is congeneric with Troohus Kolmodini and T. Wishyensis, Lind- 

 strom. • Indeed it is closely allied specifically to these Gotland shells, es- 

 pecially to the former. Whether Lindstrom was justified in referring 

 these species to Trochus, or not I have not decided, though inclined to 

 doubt it.'' In the writer's judgment, the reference of M. Billingsana to 

 the Linnsean genus Trochus, as now defined, would be almost as unsatis- 

 factory as its original reference to Murchisonia has proved to be. Its 

 surface markings are remarkably similar to those of Halo-pea Harmonia, 

 Billings. 



Pleurotomaria bispiralis, Hall. 



In their memoir on the Guelph Fauna in the State of New York, 

 Clarke & Ruedemann regard this species as a Lpphospira. Ulrich, how- 

 ever, dissents from this conclusion and gives the following reasons for his 

 dissent, in a letter dated January 20, 1906. "P. bispiralis, Hall. As 

 fio-ured by Clarke and Ruedemann (pi. 10, figs. 7 and 8) this species cannot 

 justly fall under Lophospira. Its relations seem to me to be altogether 

 di6ferent, the band as represented being distinctly concave instead of con- 

 vex. The characters shown in figs. 7 and 8 recall Eotomaria on the one 

 hand (whorls too full below) and the aberrant Plethospiroe recently dis- 

 tinguished as Ulrichospira by Miss Donald. Without good specimens I 

 hesitate to decide its position. Clarke and Ruedemann's figure 6, if the 

 drawing is correct, seems to me to represent something quite different. 



