30 CLASS III. GASTEROPODA. ORDER III. CERVICOBRANCHIATA. 
CALYPTRA4A, Lamarck. 
Testa conoidea, superné plus minusve convexa, lamina basali solida in- 
terdum sustentata; extis aut levis aut striata, interdum spinosa, 
vel foliata ; vertice subcentrali, imperforato ; appendice interna vel 
cyathiformi, vel spirali. 
Although Lamarck has undoubtedly become entitled to the credit of 
establishing many of the genera that are now commonly adopted, it 
must be remembered, that the greater part of them were certainly anti- 
cipated by the earlier naturalists in the sectional divisions of such as were 
then recognized. The Calyptrez were thus distinguished, and had been 
long regarded as an important section of the Patelle, including, as we 
have already noticed in our observations on the preceding genus, all 
those species whose shells exhibit an internal appendage approaching 
to the form of an inverted cup. Now, however, the genus Calyptrza 
may be said to include all the Capulacea in which the internal appendage 
does not exhibit the crepiduliform horizontal plate immediately cross- 
ing the aperture ; thus connecting the several variations of growth that 
are at present known to exist between the two extreme forms of the cup 
and the slipper. The intermediate passage exhibits a complete trochi- 
form growth (vide Pl. CXLIV. Fig. 2.), and has been separated as a genus 
by De Montford under the title of Infundibulum ; Lesson, however, in the 
‘ Voyage de la Coquille,’ distinguishes the several varieties of the internal 
shelly development by the following seven divisions, adopting them as 
subgenera: Crepidula, Crepipatella, Sigapatella, Trochapatella, Calyptrea, 
Calypeopsis and Syphopatella. 
We have now to notice a new and remarkable property which has 
been lately discovered by Mr. Cuming to belong to a mollusk whose 
shell is closely allied to that commonly known as the Calyptrea equestris. 
In the course of his late researches amongst the Philippines, our indefati- 
