4.')4 Miscellaneous. 



post if convenient, after the receipt of the Boxes, with these words 

 alone, or instead of them any other observation you consider 

 necessary. 



"As stated to you before, I can vouch for the accuracy of what I 

 have published respecting the Type or Xew Specimens among these 

 Sponges; and that is all that Science requires or can demand, either 

 from my head or my pocket, grain itoush/. 



" I am, my dear Thomson, 



Yours very truly, 

 " To (Signed) He>rt J. Caeter." 



Professor Sir WyvilJe Thomson, 

 20 Palmerston Place, 

 Edinburgh" 

 Of the Boxes having reached their destination I had notice by the 

 receipt of the "Postal Card" on the 28th March, signed ''C. W}'' T.," 

 and stating that they had " arrived all right," but had " not " been 

 " opened." So far I am no longer accountable for these specimens. 

 Budleigh-Salterton, April 25, 1877. 



On the first Phenomena of the Development of Echinus miliaris. 

 By M. A. GiARD. 



The important controversies to which the investigation of the first 

 development of the ogg of the Echinodermata have given rise have 

 led me this winter to undertake a series of researches upon the 

 common urchin of the shores of the Boulonnais, Psammechinus 

 miliaris. As a term of comparison in some difficult points I had 

 the eggs of the common starfish { Aster acanthion ruhens). The 

 spawning ceases in both species towards the end of March. 



The methods employed by me are those of direct observation and 

 of coloured preparations. The latter were especially useful for the 

 observation of the cunjolytic figures (Auerbach) or amphiasters (H. 

 Fol). I obtained excellent results by employing acetic acid, ammo- 

 niacal carmine, and picric acid, applying these reagents successively 

 and in very small quantities. The preparations thus obtained are 

 very beautiful ; but, unfortunately, they cannot be preserved more 

 than a few days. 



Besides the mucous envelope the egg of Ecliinus miliaris possesses 

 a veiy delicate vitelline membrane, and this even before fecunda- 

 tion, as has been asserted with regard to allied species by 0. Hert- 

 wig and Perez. A little while before maturity the germinal vesicle 

 presents the reticulum characteristic of old nuclei. The nucleolus 

 contains an irregular nucleolinus. "When the egg is mature, the 

 germinal vesicle quits the central point and enters upon re rogres- 

 sion. Its elements, mingled with those of the nucleolus, form an 

 amoeboid mass with more or less torn outlines, which soon attains 

 the periphery of the vitellus, when it divides into two parts, pro- 

 ducing a caryolytic figure. One of the stars is directed towards the 

 centre of the egg, and very rapidlj' acquires the form of a rounded 

 nucleus. It is this nucleus that 0. Hertwig regards as the germinal 

 spot, which has escaped the transfoiTnation affecting the germinal 



