NO. 7 OPINIONS 115 TO 123 31 



OPINION 121 



Necessity for Suspension of Rules in Case of Agasoma 

 Gabb^ 1869, type sinnatum, Not Proved 



Summary. — As the arguments submitted for Suspension of the Rules in 

 the case of Agasoma have not been convincing to the seven consulting con- 

 chologists and paleontologists who have studied this case, the Commission 

 does not see its way clear to approve Suspension, Agasoma Gabb, 1869, type 

 sinnatum, is hereby placed in the OfiScial List of Generic Names. 



Presentation of case. — Hoyt Rodney Gale, of Leland Stan- 

 ford Jr. University, has submitted the following case : 



In the " Paleontology of California," Volume 2, page 46, 1869, W. M. Gabb 

 described a new genus which he called Agasoma. After describing the genus he 

 lists two species, Agasoma gravida and Agasoma simiata, both of which he had 

 described as Clavella in an earlier part of the same volume, which had been 

 published separately in 1866. In both places Agasoma gravida is placed before 

 the other species, and it is mentioned as being " abundant," whereas sinnala 

 is mentioned as " a rare shell." There can be little question but that Gabb had 

 the common shell more in mind when describing the genus. The common shell 

 has since then been well-known to all West Coast paleontologists and has be- 

 come the type of the "Agasoma gravidum zone " of the Oligocene. It has been 

 considered the type of the genus by West Coast workers, and other species simi- 

 lar to it have been described; whereas Gabb's two rather poor specimens of 

 sintiatum have stood practically alone. However, it being such a generally 

 recognized fact that Agasoma gravidum was the type, no one on the West Coast 

 took the pains to state it definitely until English revised the group in 1914 

 (Univ. Calif. Publ., Bull. Dept. Geol. Sci., vol. 8, p. 245, 1914). In 1922, Trask, 

 thinking sinnatum generically distinct, proposed the name Koilopl,cnra for it 

 (Univ. Calif. Publ., Bull. Dept. Geol. Sci., vol. 13, p. 157, 1922). In the mean- 

 time, however, and many years before English's paper was published, Cossman 

 wrote the type of the genus as sinnala (Essais Paleo. Comp., vol. 4, p. 148, 

 1901). This fact was first brought to the attention of West Coast paleontologists 

 by Stewart who proposed the name Brticlarkia for what had been considered 

 typical Agasoma (Proc. Acad. Nat. Sci. Phila., vol. 78, p. 399, 1926). 



Cossman knew nothing at all about the situation, not realizing that one of 

 the groups is little more than a curiosity, not realizing that the other group is 

 so important that a change in name would be a source of annoyance and incon- 

 venience to geologists as well as paleontologists, who even at that time knew 

 the species of Agasoma as important horizon markers, not having heard of the 

 important new species of Agasoma previously described by Cooper (Bull. No. 4, 

 Calif. State Mining Bureau, p. 53, pi. 5, fig. 63, 1894), probably never having 

 seen a specimen of gravidum, and surely never having seen a specimen of 

 sinnatum. Thus Cossman's work is not a revision of the genus, and although 

 the old rule requiring a man to " revise " the group in order to make the citation 

 of the type valid does not hold, there is at least a strong feeling against his 

 method. Cossman clearly should not have taken it upon himself to arrange a 



