1892.] Embryology. 



The embryo elongates and hatches in an imperfect state wii 

 pairs of setigerous parapodia, partly formed fourth somite, h 

 tail, anal and cephalic tentacles. 



A just estimate of the paper can be formed only with the 

 ance of the full account of the American species Studied l»y 

 From the preliminary account it seems that, allowing for th 

 ences due to a direct and an indirect development and the di 

 offered by an opaque as opposed to a transparent object ; the c 

 ogy of these two species of Nereis has very much in common, s 

 ening the theoretical conclusions that may be drawn from eit 

 rendering of little use the previous imperfect studies of the sa 



Development of the Lobster. 1 — Mr. H. C. Bumpus publishes 

 a contribution to the Embryology of the American Lobster. Many 

 females seem to be impregnated with spermatozoa long before they are 

 able to deposit eggs, which cannot take place until a year if not two 

 years later. The author has discovered in the female a receptive 

 apparatus for the spermatozoa. " This organ lies at the posterior end 

 of the sternum of the female lobster, resting between the bases of the 

 IV and V pairs of thoracic appendages." 



The eggs are deposited (on abdomen) in July and August, and 

 develop rapidly so long as the water is relatively warm. Certain pre- 

 cocious eggs may exceptionally hatch before winter. This is not the 

 rule, for ordinarily the eggs hatch between the middle of May and the 

 middle of July of the following year. 



The nucleus of the egg divides and re-divides before the protoplasm 

 (and yolk) of the egg shows any traces of division. When nuclear 

 division has taken place about three time elevations and furrows appefl r 

 on the surface, at first only at the animal pole. 



Later the lower pole is divided and all the furrows extend deeper 

 into the yolk, "though there is shown a central mass of yolk that 

 remains undivided." On the third or fourth day after oviposition 

 the Gastrula is formed. 



The rest of the paper deals with the later stages of development. 



Embryology of the American Alligator.— Dr. 8. F. Clark 



publishes in the September number of the Journal of Morphology 3 a 

 paper on the habits and embryology of the American Alligator. The 



