84. Messrs. J. C. Melvill and J. H. Ponsonby on 
of Amphioxus in the series of higher animals. Nevertheless, 
that it constitutes an actual transition between the two great 
groups of the animal kingdom can be asserted of it equally as 
little as of an Orthonectid or of Zrichoplax ; for indeed we 
have here isolated links before us for which we cannot find a 
place in our system, beautifully and ingeniously constructed 
though it is, and which tend to prove how litle Nature is 
amenable to a dogmatic treatment on our part, a treatment 
which unfortunately appears to take the upper hand too much 
in the biological sciences, and which would gladly exclude 
everything which does not fit into its narrow frames. 
XIII.—Deseriptions of Seven new Species of Terrestrial 
Mollusca from South Africa. By JAMES Cosmo MELYVILL, 
M.A., F.L.S8., and Jonn Henry Ponsonsy, F.Z.S8. 
[Plates IV. & VI.] 
1. Helix (Pella) trichostetroma, sp. n. 
(BINTV. fig.,9:) 
HT. testa angustissime sed profunde umbilicata, corneo-fusca, con- 
vexiuscula, sublevi, longitudinaliter oblique tenuistriata, undique 
lirulis spiralibus minutissime decussata; anfractibus quinque, 
ultimo in medio carinato, carina capillis brevibus accincta ; aper- 
tura lunari-ovata ; peristomate simplici ad marginem columellarem 
reflexo. 
Long. 5°50, lat. 7-50 mill. 
Hab. Port Elizabeth, 8. Africa. 
Judging from the description of Helix petrobia (Benson), 
recorded from High Constantia, Cape of Good Hope, but of 
which we have not been able to examine the type, the species 
under discussion would seem to differ chiefly in the acutely 
angled keel, fringed with regular, short, epidermal hairs, also 
in the form being more convex, colour dull brown, with no 
fulvous tinge, and other minor distinctions. 
2. Helix (Pella) epetrima, sp.n. (PI. IV. fig. 3.) 
H. testa anguste umbilicata, depressa, tenui, cornea, subpellucida, 
undique confertim striatula, striis obliquis regularibus, spira de- 
presso-convexa ; anfractibus quatuor, convexiusculis, ad suturas 
impressis, ultimo anfractu rapide accrescente; apertura lunari; 
