ZOOLOGY AND BOTANY, 'MICROSCOPY, ETC. 925 



The nature of the various parts of the spermatozoid is discussed at length, 

 but does not readily admit of summary. 



Fate of the Blastopore in Rana temporaria.* — Mr. H. Sidebotham, 

 from the examination of more than sixty embryos, is more inclined to 

 agree with the acoount given by the late Prof. Balfour in his ' Com- 

 parative Embryology ' than with those of Spencer, Johnson and Sheldon, 

 or Durham as to the fate of the blastopore in the frog. He differs from 

 Balfour in so far as he finds that the neural folds do not inclose the 

 blastopore, the closure of the latter being effected sixbsequently to the 

 meeting of the neural folds. From Spencer he differs essentially, for 

 he finds that the anus is not derived from a persistent blastopore, but 

 is formed from an independent proctodceal invagination. 



Development of the Frog.f — In the new third edition of his manual 

 on the Frog, Prof. A. Milnes Marshall has added a chapter on its 

 development, which should prove useful to many classes of students. 

 It is illustrated by several woodcuts, some of which are new and very 

 instructive. 



Eggs of Alligator lucius.l — Prof. S. F. Clarke has examined the 

 nests and eggs of the alligator. He states that the eggs are white, 

 elliptical, and varying from 39 to 45 mm. in the shorter diameter, and 

 from 67 to 88 mm. in the longer. The shell is thicker than that of a 

 hen's egg and more brittle, and the shell-membrane is also thicker. The 

 white has the consistency of a very thick jelly, so that it will adhere to 

 the yolk after the shell-membrane is removed ; the yolk is spherical, 

 and of the faintest yellow or straw colour ; the white forms a very thin 

 pellicle, and as, after the first day, it is almost impossible to get off the 

 membrane without rupturing this thin pellicle, and so breaking the 

 embryo, the eggs are very difficult to work with. 



Eggs and Larvae of Teleosteans.§ — Sig. F. Raffaele gives a pre- 

 liminary account of his observations on the ova and larvae of Teleosteau 

 fishes. He starts with emj)hasizing the necessity for rigorous comparison 

 of pelagic and ovarian eggs, and for making the series of larval forms 

 as complete as possible. He proceeds to describe the characters of 

 certain eggs from the Gulf of Naples, which resemble those referred by 

 Agassiz aud Whitman to Osmerus mordax Gill. The appearance of the 

 hatched larvae proved them to be Clupeids, and it seemed likely that 

 they were the common sardines (Clujpea pilcliardus). A noteworthy 

 character, which begins to appear in very young larv« (15-20 days), is 

 a series of regularly disposed transverse folds of the intestinal mucous 

 membrane, from the pylorus to the anus. This appearance, which 

 recalls the spiral valve of Elasmobranchs, and still more that of Ganoids, 

 has been described by Cuvier and Valenciennes in G. alosa, C. pilchardus, 

 and in some allied forms. The author believes that hints of natural 

 affinities may be profitably looked for in the structure of the vitellus. 



The author also describes || the ova and larval form of the anchovy 

 {Encjrmdis encrasicholus). The eggs had a much elongated ellipsoid 

 form ; the very transparent vitellus exhibited large vesicular segments ; 

 the delicate capsule was perforated by a single micropyle at the inferior 



* Quart. Journ. Micr. Sci., xxix. (1888) pp. 49-54 (1 pi.), 

 t ' Tlie Frog,' Srd ed., 1888, Manchester aud London. 

 j Zool. Anzeig., xi. (1888) pp. 568-70. 



§ Boll. Soc. Nat. Napoli, i. (1887) pp. 53-8. || Ibid., pp. 83-4. 



1888. 3 R 



