ZOOLOGY AND BOTANY, MICROSCOPY. ETC. 23 



two eggs weighing 125 grm. each, and with dimensions 79 by 51 mm. 

 and 7!) by 50 mm. ! He also reports spherical and retort-shaped eggs. 



Ichthyosaurus with Embryos.* — A. Smith Woodward notes that 

 the British Museum has recently acquired two fine specimens of this 

 viviparous extinct reptile. One specimen, discovered and described by 

 J. Chaning Pearce in 1846, is from the Lower Lias of Somersetshire, 

 appears to be /. communis, and contains one relatively small embryo. 

 The other specimen, referable to /. quadriscissus = I. acutirostris, is 

 from the Upper Lias of Wiii'temberg, and contains at least six embryos. 

 The largest number of embryos hitherto observed in one individual of 

 /. acutirostris is seven, and it is interesting to note that in each recorded 

 case of more than one contained embryo, the young are always directed 

 with the snout forwards. 



Evolution without Mutation.f — C B. Davenport refers in parti- 

 cular to the North American song-sparrow {Melospizci), whose varieties 

 are connected by intermediate forms, and to species of Scallop. He 

 concludes that the best evidence for slow evolution is found in wide- 

 rangiug species, which, while differing greatly at the limits of their 

 range, exhibit all gradations in intermediate localities {Melospiza, 

 Pecteii) ; also in fossil series {Pecten eboreus and F. irradians), where 

 the change from one horizon to the next is of the quantitative order. 

 Thus, evolution may take place without mutation. It is no more 

 justifiable to maintain that all evolution is by mutation than that 

 evolution has always proceeded by slow stages. 



Black Sheep in the Flock.J — C. B. Davenport inquires into the 

 origin of black sheep in a fiock. They crop out in flocks of breeding 

 ewes and rams that are wholly white. When a quality suddenly arises 

 from parents that have its opposite, the probability is that the two 

 opposed qualities follow Mendel's law in inheritance, and that the new 

 filial character is recessive, the parental opposite dominant. The author 

 states four tests of recessiveness, and tests the recessiveness of the black 

 coat in sheep by Alexander Graham Bell's "Sheep Catalogue" (1904). 

 The conclusion of the whole matter is that black wool colour in sheep 

 behaves like a Mendelian recessive characteristic. 



h. Histolog^r. 



Collagenous Connective Tissue Fibrils in Matrix of Cartilage, 

 Dentine, and Bone.§ — F. K. Studnicka has applied the method of 

 Bielschowski (for demonstrating neuro-fibrils) in showing the occurrence 

 of connective tissue fibrils in the hyaline cartilage of the lamprey, in the 

 dentine of dogfish scales, and guinea-pig's incisors, in the bones of 

 Belone, and the human foetus. 



Histology of Metamorphosis in Anura.|| — Dr. Duesberg discusses 

 the atrophy of the tail and the metamorphosis of the intestine. As 



* Geol. Magazine, iii. (1906) pp. 443-44 (1 pi.). 



t Jouru. Exp^r. Zool., ii. (1905) pp. 137-43. 



X Science, xxii. (1905) pp. 674-5. 



§ Anat. Anzeig., xxix. (1906) pp. 334-44 (10 figs.). 



II Arch. Biol., xxii. (1905) pp. 163-221 (2 pis.). 



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