984 SEC. 18. BIOLOGY. 



3837. Left Half of the Skull of a Sturgeon (Acipenser 

 sturio), stained to show the cartilaginous cranium. 



The Anatomical Department, University Museum, Oxford. 



This preparation was placed for several hours in staining fluid, which has 

 tinted the cartilaginous cranium whilst leaving the bony elements with their 

 natural white colour. Prepared by Mr. Robertson. 



3838. Skull of a Sturgeon (Acipenser sturio}, stained to 

 show the cartilages. 



The Anatomical Department, University Museum, Oxford. 



The opercular bones of both sides have been removed, also the shoulder 

 girdle, parietal and frontal bones of the left side, to show the cartilaginous 

 cranium. Prepared by Mr. Robertson. 



3839. Set of Wax Models, to illustrate the Development 



of the Trout (Trutta fario), containing 21 preparations, in- 

 cluding 7 sections. The preparations can be viewed by transmitted 

 light. Magnified 30 diameters. 



Dr. A. Ziegler, Freiburg, Baden. 



This series is the latest work of the exhibitor, and the 2 1st series of his 

 scientific wax preparations for illustrating biological facts, and particularly the 

 changes during development. These wax models are copied from nature, and 

 enlarged so as to be useful for teaching purposes. Compare the accompanying 

 prospectus and account of physiological preparations in wax for the use of 

 English readers. 



A full account of the development of the trout's egg will be found in 

 Zeitschrift f. wiss. Zool., Vol. 22, Part IV., Plates 32 and 33, and Vol. 23, Part 

 I., plates, 1, 2, 3, and 4, in papers by Professor Oellacher of Innsbruck. 



3839a. Collection of Preparations for the Study of the 



Embryology of the Sterlet (Acipenser ruthenus), from the 

 segmentation of the egg to the one } r ear old fish. 



Ph. Owsiannikoff, University of St. Petersburg. 



The first artificial fecundation of the eggs of this fish was made by M. 

 Ph. Owsiannikoff, in the year 1869, at Simbirsk on the "VVolga, and in the 

 same year a small quantity was brought by him to St. Petersburg. The 

 exhibited embryos presented have grown up in an aquarium in the study room 

 of M. Owsiannikoff, who wishes to present them to the South Kensington 

 Museum. 



3839b. Preparations on the Embryology of the Sterlet 

 (Acipenser ruthenus). 



Ph. Owsiannikoff, University of St. Petersburg. 



The time is fixed approximately, as at an early stage temperature and 

 quantity of food have a great influence on the development. No. i. First day, 

 the hole of Rusconii forms the half of the egg. No. 2. Second day, morning, 

 the hole of Rusconii is smaller. No. 3. Second day, evening, the hole of 

 Rusconii is very small. No. 4. Fourth day, the hole of Rusconii has dis- 

 appeared. No. 5. Fifth day.. No. 6. Sixth day. No. 7. Seventh day. No. 8. 

 The third and fifth days after their coming out from the egg. No. 9. About 

 a week after their coming out. Nos. 10, 11, 12, 13. From two to four weeks. 

 No. 14. About six weeks ; bastard of an Acipenser Giildenstaedtii (soft roe), 

 and of an Acipenser ruthenus (hard roe). No. 15. About two months. 

 No. 16. About a year ; reared in an aquarium. If there is plenty of fooi the 

 fish can attain about double this size in the same period, 



