186 SUMMAKY OF CUKKENT KESEAKCHES RELATING TO 



these Insectivores, they all belong to the Coenorhinata, and agree with 

 most higher Mammals, such as Carnivores and Ungulates. 



On the other hand, Tupaia and Macroscelides agree in having a 

 Polyprotodont Marsupial type of structure, and cannot have any near 

 affinity with the typical Insectivores ; and the order Menotypli la, to which 

 they belong, must be removed far from the Insectivora and placed in 

 quite a different alliance, not far from the early Marsupials. 



Although Chrysochloris has been generally regarded as allied to 

 Centetes, it'^is not at all closely related to it. Like Tupaia, Chrysochloris 

 belongs to the ^Archseorhinata, but it cannot belong to the order Meno- 

 typhla. The peculiar structure of the molar teeth of Chrysochloris has 

 suggested an affinity with Centetes, but a similar type of molar occurs in 

 the Marsupial Notoryctes, and the resemblance is probably one of con- 

 vergence. The development of Chrysochloris must be inquired into, but 

 in the meantime Broom has no hesitation in removing it from the 

 Insectivora and placing it in a distinct order, for which the name 

 Chrysocliloridea, proposed by Dobson, may be retained. 



Penis of New-born Bear.*— Ed. Retterer and H. Neuville describe 

 this in a brown bear's cub 18 cm. in total length. The cub was covered 

 with hair, whereas Weber has described it as being born quite naked. 

 The body of the penis includes an unpaired corpus cavernosum, a fibro- 

 elastic envelope or fascia, and a corpus spongiosum. The glans and the 

 adjacent part of the body of the penis had a corpus cavernosum formed 

 of precartilaginous tissue of precisely the same structure as that of a 

 newly-born dog. Later on there is formed an S-shaped bone. The 

 particular point of the investigation is to show the resemblance between 

 the dog type and the bear type'in the structure of the penis, thus corrobo- 

 rating the conclusion of palaeontologists that Cynoids and Arctoids had 

 a common ancestor. 



Origin of Blind Fishes.f — Jacques Loeb has found that embryos 

 with degenerated eyes can be produced by heterogeneous hybridization, 

 e.g. Fimdulus heteroclitus $ and Menidia. In these cases there is 

 usually no cu'culation, and this may account for the anomalous con- 

 dition of the eye. Moreover, blind embryos of the pure breed of 

 F. heteroclitus may be produced by the addition of KCN to the 

 sea-water. 



It is shown that immediately after fertiUzation (by sperm of its own 

 species), and during the early stages of segmentation, the egg of 

 F. heteroclitus is rapidly killed or injured if it is exposed to a constant 

 temperature of about 0' C. (or slightly above) ; while it may be exposed 

 to a slightly higher temperature' (e.g. 7' C.) for weeks without being 

 injured. If the egg is exposed to the low temperature after the 

 embryo is once formed, it can resist the low temperature from 0° to 

 2" C. for weeks without permanent injurious effects. If eggs of F. hete- 

 roclitus are fertilized with the sperm of the same species, and exposed 

 immediately after fertiUzation for a number of hours to a temperature 



* C.R. Soc. Biol. Paris, Ixxviii. (1915) pp. 327-30." 

 t Biol. Bulletin, xxix. (1915) pp. 50-67 {13 figs.). 



