Tak. Mr. T. H. Withers on 
C. caretta affix themselves to the surface of the turtle to- 
day.” 
Although many specimens have been found attached to 
ammonites, in no case am I aware that they are attached to 
the actual shell, the ammonite being represented by a chalk- 
cast. Whatever the mode of attachment, it cannot be said to 
be truly comparable to the mode of attachment of Coronula 
or Chelonibia. Tomy mind it is more probable that the shell of 
Stramentumwas attached only by the extremity of its peduncle, 
and was pressed against the side of the ammonite during 
fossilization. While the Kansas examples of Stramenium 
haworthi on the two slabs in the Geological Department of 
the British Museum appear to have been attached to a strap- 
like organism, of which only a stain remains, the type was 
said by Logan to be attached to a shell of Ostrea congesta 
by the extremity of its peduncle. Dr. H. Woodward appears 
to have doubted this, but there is a photograph of the type 
exhibited with the above-mentioned slabs in the British 
Museum, and this conclusively shows that that specimen, at 
any rate, was so attached. 
Comparison with other Genera and Phylogenetic Position. 
The structure of Stramentum as now revealed by the new 
material certainly shows it to be more anomalous than was 
thought. So far as our knowledge goes, it differs from all 
other cirripedes, both recent and fossil, in that all the valves 
of the capitulum are paired, and that the outermost or sub- 
carinal and subscutal rows of peduncular plates do not 
overlap or intersect each other. The shell could therefore 
readily be divided along the sutures formed along the 
carinal and scutal margins. It further differs from all 
recent cirripedes in the marked disparity in size of the 
lateral plates of the peduncle as compared with those of the 
subscutal and subcarinal series. ‘There appears to be a 
similar disposition of the peduncular plates in the Cretaceous 
genera Sguama(Senonian) and Loriculina (Senonian). How 
far these genera are related it is difficult to say, for we 
know so little of their precise structure. Further investiga- 
tion may prove Loriculina to be congeneric with Stramentum, 
for the presence of a comparatively large rostrum in the 
figure of the genotype may not be substantiated. Squama, 
which is so far confined to the Kansas chalk and occurs at a 
slightly lower horizon than Stramentum haworthi, is known 
only from the inadequate figures and descriptions of Logan. 
When the precise structure of the genus is known it will 
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