ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
303 
y. Gastropoda. 
Development of Shell-Ornamentation in Marine Gastropods.*— The 
Countess Maria von Linden has investigated this subject in order to 
determine whether Eimer’s well-known views as to the development of 
the markings of animals are applicable in this case. From a study 
both of fossil shells, and of various stages in the life-history of recent 
forms, the author concludes that the development of shell-sculpture, 
both phylogenetically and ontogenetically, takes place as follows. The 
first stage is a thickening of the lines of growth to form transverse 
ridges; then, first transverse, and secondly longitudinal, rows of tubercles 
are developed, and finally longitudinal bands appear. Thus transverse 
sculpturing always precedes longitudinal (cf. Eimer’s results). The 
development of surface-sculpturing is worked out in detail, and applied 
to the classification of the species of the genera Voluta , Strombus, 
and Conus, of which genera genealogical trees are given. As to 
coloration, the author finds that the colour is due to two pigments, a 
brown and a black ; in the species of Helix , at any rate, similar granular 
pigment occurs in the epithelial and connective-tissues, especially in 
spring. Just as the sculpturing of the shell is due to an increased 
secretion of lime at particular parts of the mantle, so the markings are 
produced by a special pigment-production at certain spots. 
As to the cause of the sculpturing and markings of shells, the author 
follows Eimer in rejecting the theory of their usefulness and consequent 
origin by the action of natural selection, and in accepting, as an efficient 
cause, the inherited effect of external conditions. She emphasises 
especially the fact, that during life the surface of the shell is often so 
covered with algss, that the markings are quite concealed. The 
similarity between the colours of shells and algae of similar habitat 
she is inclined to regard as the result of like physico-chemical con- 
ditions. 
Buccal Cartilages of Gastropods. f — M. A. Amaudrut describes four 
pairs of cartilages in the buccal mass of the limpet, a pair of inferior 
laterals in addition to the superior laterals, the anterior pair, and the 
posterior pair described by Geddes and Gibson. He traces the modi- 
fications of fusion, &c., in Nerita, Navicella, Fissurella, Turbo, Trochus , 
Haliotis , &c., and the associated changes of musculature. 
Melanie Pigment of Limnsea.]:— Dr. E. Andre discusses the black 
pigment found in minute spherical granulations in the cells of the 
external epithelium of Limnsea, on the region covered by the shell, or 
sparsely between the cells in the connective layer around the buccal 
mass, the food-canal, &c. This melaine is insoluble in water, alcohol, 
ether, alkalies, and most acids ; it is not digested by artificial gastric 
juice, and can thus be separated from the tissue ; it contains iron, and 
so on. In short, its properties are the same as those which Girod has 
assigned to the melaine in the ink-bag of Cephalopods. It must be 
noted that it is not melanin , which occurs in little rods, and has different 
chemical properties. “ It is, perhaps, as is the case with many pigments, 
* Zeitschr. f. wiss. Zool., Ixi. (1896) pp. 261-317 (1 pi.). 
t Comptes Rendus, exxi. (1895) pp. 1170-2. 
J Revue Suisse Zool., iii. (1895) pp. 429-31. 
Y 2 
