Miscellaneous. 469 



reproduce themselves with an altered scale-covering, instead of 

 being constituted, as in the original, phylogenetically oldest forms 

 of the family in question, on the primary tail, in all newly acquired 

 parts exhibit an extensive differentiation from the form originally 

 manifested, tubercle-scales, crests, spines, and keeled scales not being 

 reproduced. 



2. In the regeneration of the tails of all Saurians which repro- 

 duce them with an altered form of scale, the existing outer segmen- 

 tation of the scaly coat, as well as the development of the preformed 

 points of rupture of the skin, together with the differentiation of a 

 vertebral column, is lost. 



3. In some cases in which the scale-covering of the tip of the 

 primary tail is different from that of the substituted tail the 

 secondary tail agrees with the normal tail-tip, which consequently 

 in this respect shows itself really in the original condition. 



4. Differentiations of the scale-covering, which are wanting in 

 the regenerated tails of lizards, such as tubercles, ridges, &c, are 

 also not to be recognized in the embryos of the same species until 

 they attain a certain age. 



5. The regeneration of the tail generally fails to take place, or 

 takes place to a very limited extent, when it has undergone a special 

 differentiation into offensive or prehensile organs. 



6. In cases of a second regeneration the tertiary tail agrees 

 entirely with the secondary so far as the scale-covering is con- 

 cerned. 



7. Within the same family the regenerated tails of all forms 

 agree, especially in the rule as to the arrangement of the scales. — 

 Sitzungsb. kais. Ahad. der Wiss. Wien, Jahrg. 1896, pp. 34-35. 



On the Mollusca (Prosobranchiata and Opisthobranchiata, Scctphopoda 

 and Lamellibranchiata) Dredged by the Austrian Deep-sea Expe- 

 ditions of H.M.S. ' Pola ' in the Years 1890-94. By Dr. Rudolf 

 Sturany. 



The question of the uniformity of the Molluscan fauna of the 

 greater depths of the Mediterranean Sea (from about 400 metres 

 onwards), which Fischer asserted and has proved from the results of 

 the ' Travailleur ' Expedition, are confirmed afresh by the dredgings 

 of the ' Pola.' Further, the material obtained is of a kind to 

 strengthen the conclusions of Dr. v. Marenzeller, recently published, 

 which, based upon the nature of the various Echinoderms dredged 

 at different depths and the uniform character of the whole deep-sea 

 fauna from 200 metres up to the greatest depths, brought out the 

 fact of the absence of a defined abyssal fauna. 



Again, an Atlantic origin has very rightly been ascribed to the 

 deep-sea fauna of the Mediterranean, from the fact that many 

 abyssal mollusks of this basin are identical with Atlantic and North- 

 Atlantic forms and occur in the Tertiary deposits of Sicily and 

 Italy, and their ingress referred to a time when there was a much 

 freer communication between the Atlantic and Mediterranean seas 

 than exists at present (Jeffreys, Fischer). 



