Miscellaneous. 181 
related to L. Lebourt, described by Mr. Percy Sladen before this 
Society in 1879; but it also has affinities with L. cincinnatiensis 
and L. squamosus. From all these, however, the present specimen 
differs in having the pyramid in the middle of the interradial space, 
in possessing shorter arms, and in being much smaller, This fossil 
is to be named Lepidodiscus Milleri, after Mr. Hugh Miller, under 
whose direction these fossils were collected by Mr. J. Rhodes. 
2. “ Archewopneustes abruptus, a new Genus and Species of 
Echinoid from the Oceanic Series in Barbados.” By J. W. 
Gregory, Esq., B.Sc., F.G.S. 
This genus belongs to a group of Echinoidea which has given 
some trouble to systematists, owing to the union of the characters 
of the orders Cassiduloidea and Spatangoidea; the other genera 
belonging to the group are Asterostoma, Pseudasterostoma, and 
Palwopneustes. The evidence of the new Echinoid throws light 
upon the affinities of these genera, The main points suggested by - 
a study of the new species are :—(1) the abandonment of the name 
Pseudasterostoma aS a synonym of Palwopneustes; and (2) the 
inclusion of the true Asterostoma, Palwopneustes, and Archwopneustes. 
in the Adete Spatangoidea, whereby the Plesiospatangidee are left as 
a more homogencous family, though bereft of the chief interest 
assigned to it. 
A tabular summary of the nomenclature of the group is given. 
The best-known fossil species of Asterostoma and Palwopneustes 
occur in Cuba, in deposits referred to the Cretaceous owing to the 
resemblance of these Echinoids to the common Chalk Hehinocorys 
scutatus. The new genus includes a species from the same deposit, 
which is probably of the same age as the Bissex Hill rock from 
which the new species was obtained; this is at the top of the 
Oceanic Series, and belongs to the close of the great subsidence. 
MISCELLANEOUS. 
Note on Abnormalities in the Crayfish (Astacus fluviatilis). 
By W. N. Parxer, Ph.D. 
Wuite a number of crayfishes were being dissected by my students 
last month I noticed that three of the specimens presented certain 
abnormalities which, although perhaps not so interesting as the case 
recently described in this Journal by Benham*, are probably worthy 
of record. 
Specimen I.—On the left side, in addition to the normal pleuro- 
branch of segment 13, a small but well-developed gill was present 
on the wall of segment 12 in place of the usual rudimentary style. 
This gill was about three quarters as long as the pleurobranch 
normally present. 
Specimen I1.—The last arthrobranch of the left side, 7. e. the 
* “Note on a Couple of Abnormalities,” ‘ Annals,’ ser. 6, vol. vii. no. 39, 
March 1891, p. 256, 
