ZOOLOGY AND BOTANY, MICROSCOPY, ETC, 161 



stages the anterior end of the notochord is connected with the band 

 uniting the pre-mandihibar head-cavities, and thereby with the posterior 

 wall of the hypophysial diverticulum. But there is great diversity later 

 on when the base of the cranium has become cartilaginous. In Varanus 

 and Cis/Niio there are notochordal nodules just behind the hypophysial 

 primordium, even in the sella turcica. In Gongylus ocellatus and 

 Cerastes cornutus at the same stage the anterior end of the notochord is 

 much further back and not in the vicinity of the hypophysis. J. A. T. 



Development of Auditory Apparatus in Sphenodon. — F. R. Wyeth 

 {Pnir. Royal Soc, Series B, l'J20, 91, 224-8). The cartilaginous 

 auditory capsule and the anterior cornu of the hyoid are products of 

 two connective-tissue proliferations, and there are two centres of chon- 

 dritication — one hyoidean and one capsular— originally separated by an 

 intervening tract of mesenchyme. It is concluded that the columella 

 auris is derived from the hyoid arch, with which it is continuous 

 throughout all stages of development, and that the extra-stapedial 

 cartilage is primarily united with the anterior cornu of the hyoid. The 

 supra-stapedial cartilage (including the recurrent process) is developed, 

 and persists as an outgrowth from the extra-stapedial cartilage, and is 

 therefore a hyoidean derivative. The auditory capsule contributes, at 

 most, a portion of the foot-plate of the stapes, which is probably partly 

 capsular and partly hyoidean in origin. Tliei-distal portion of the stapes 

 is exclusively hyoidean. J. A. T. 



Thyroid Gland of Anura in Relation to Metamorphosis. — C. 0. 

 Jexsen {Gomptes Rendiis Soc. Biol., 1920, 83, 948-9). In larvas 

 of Rana esculenta, R. arvalis, and Biifo vulgaris anomalies in the 

 metamorphosis may be correlated with peculiar states in the thyroid 

 gland. Ill abnormally precocious metamorphosis tlie follicles of the 

 thyroid gland were filled with a colloid mass with a strong affinity for 

 eosin, which points to an unusually intense secretory activity. In larvae 

 that had remained larvee through the winter the thyroid was much 

 enlarged, the follicles were swollen with a colloid with little affinity for 

 eosin, and the epithelium of the foUicles was much flattened. In giant 

 tadpoles the thyroid was much enlarged, the numerous follicles in part 

 in process of proliferation showed cubical or cylindrical epithelium ; 

 between the follicles there were in certain places cellular masses of 

 considerable volume. J. A. T. 



Pig'mentation in Larvse of Anura. — J. Nageotte {Gomptes Remivs 

 Soc. Biol., 1920, 83, 319-20). What Prenant calls the reticulum 

 of Asvadourova was described by Eberth in 1866. In tadpoles of the 

 frog there are vacuoles with liquid contents between the chromatophores 

 and the basal membrane, and forming a continuous layer. They are 

 probably homologous with Eberth's reticulum seen in Alytes, Disroylof^siis, 

 Bombinator, and other forms. They do not occiu' in the tadpoles of 

 the common toad. J. A. T, 



Grafted Embryos of Bombinator. — A. Weber {Gomptes Rendiis 

 Soc. Biol., 1920, 83, 1058-60). Young embryos of Bombinator 

 igneus at the end of gastrulation were placed in the dorsal lymphatic 



