166 T'ransactions. 
the case for the inclusion of T. coronata is not so good, because it involves 
the separation of that species from T. scutulata and T. clathrata. 
It is necessary, before going further, to determine what relative import- 
ance should be conceded to the various shell-characters. Roughly, the 
cannot be applied absolutely, because a small difference in the aperture 
might not carry the same weight as a considerable difference in sculpture ; 
also, the possibility of parallelism and convergence must be taken into 
account. Still, there is a broad relative value attached to the features 
mentioned. 
Fia. 8.—a. Tylospira coronata (Tate). (After Tate.) 
b. Tylospira scutulata (Martyn). 
formation of this callus, so that no ornamentation except growth-lines and 
a few obsolete spirals is developed on the body-whorls. If Steinmann 
and Wilekens were correct in classing T. coronata as Struthiolarella, then 
T. scutulata would also have to be included, and Tylospira would supersede 
Struthiolarella. The former genus, however, has a bisinuous outer lip, while 
the latter has a unisinuous one, so that the two generic terms should stand, 
Tylospira for the Australian and Struthiolarella for the South American 
species. 
3. Genus SrRuTHIOLARIA Lamarck, 1812. 
Genotype: Buccinum papulosum Martyn. 
(a.) S. papulosa Group. 
The apex consists of about two smooth whorls, the first planorbid ; but, 
as pointed out above, these may not represent the true protoconen. , 
The first conch-volution of the type species is the usual convex one with 
five or six spirals. Three finer exogeneous spirals (Grabau, 1902) then 
appear, while at the posterior primary spiral the whorl shows а slight 
Hu 
