ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 563 



three back teeth, — in Anornaluridaa, Geomyidae, Heteromyidse, Bathy- 

 ergidas, Dipodidae, Pedetida?, Octodontidas, and Chinchillidad, there seems 

 to be no succession of teeth. But further research is necessary to show 

 whether there may not be a replacement during foetal life, as is known to 

 be the case in Caviida?. 



Dental Ridge of Selachians.* — Paul Laaser has investigated the 

 development of the dental ridge in embryos of Spinax niger, Mustelus 

 Isevis, and Arantkias vulgaris. In Spinax the development of the teeth 

 takes place somewhat more rapidly in the lower than in the upper jaw ; 

 whereas in Mustelus the reverse is the case. Otherwise the author's ob« 

 servations appear to confirm exactly Hert wig's previous descriptions for 

 Acanthias. 



Homology of Kupffer's Vesicle.f — Fr. Kopsch notes that many sug- 

 gestions have been made as to the significance of this characteristic of 

 the embryos of Teleosts ; as that it is the homologue of the allantois, of 

 the terminal vesicle of the post-anal gut in Selachians, of the archen- 

 teron. The progress of knowledge lias, according to the author, made 

 the first position impossible, and he does not believe tbat there is any 

 evidence for the third, but is of opinion that the evidence all supports 

 the second view. Further, he believes that the post-anal gut of Sela- 

 chians and the vesicle of Teleost embryos are both to be explained as 

 remnants of the primitive food-canal which extended to the posterior 

 end of the body. As Selachians are nearer the primitive type than the 

 more aberrant Teleosts, it is natural tbat the post-anal gut should reach 

 a higher degree of development in the former than does its homologue 

 in the latter. In more detail, Kupffer's vesicle is to be regarded as a 

 part of the primitive cloaca neurenterica. 



Rearing of Sea-fish Larvse.J — Mr. Walter Garstang has made a 

 series of experiments on this subject, choosing Blennius ocellaris as the 

 subject of observation. He was successful in rearing a certain per- 

 centage of larvae through the critical stages, and believes that the essen- 

 tial conditions for the obtaining of this result are a liberal supply of 

 pure water, a moderate agitation of the water, the provision of suitable 

 food prior to the absorption of the yolk, and a constant but not excessive 

 food-supply. In regard to the food-supply it is essential that the tastes 

 of the individual larvae be considered. Incidentally the paper contains 

 some notes on the habits, &c. of Blennius ocellaris. 



Recent Teratological Literature^ — Prof. Bertram C. A. Windle 

 publishes the tenth of his very useful reports. In the experimental part 

 he summarises, inter alia, Bertacchini's || observations on the results of 

 puncturing the blastoporic rim in Bana esculenta ; Barfurth'sIT evidence 

 that the cauda bifida of amphibian larvas is due to regeneration after 

 injury ; Barfurth's ** remarkable case of a larval lamprey with three 

 tails, each containing a spinal cord, a notochord, a caudal artery, and 

 myomeres. In the section on duplicity, he summarises among others, a 



* Anat. Anzeig., xvii. (1900) pp. 479-89 (8 figs.). t Tom. cit., pp. 497-509. 

 J Journ. Mar. Biol. Ass., vi. (WOO) pp. 70-93. 

 § Journ. Anat. Physiol. Norm. Path., xxxiv. (1900) pp. 410-25. 

 | Int. Monatschr. Anat. Phys., xvi. Heft 7, 8. 

 Tf Arch. Entwickelungsmech., ix. ** Tom. cit. 



