Bihliu(jyaplucal Notices. 213 



Parley " school of naturalists is fast becoming extinct, and with it 

 its opiiosite, the purely technical. A more ^jhilosophical spirit is 

 abroad, and we trust ere long naturalists will be able to hold up 

 their heads on an equality with astronomers and mathematicians. 

 Gladly we hail in the authors of the volume before us fresh aspirants 

 to scientific honours, working in the right way ; they have already 

 done good service, and their book should be constantly open on the 

 table of every zoologist. 



Entwicklung des Hummereies, 8^c. : — On the Development of the 

 Ovum of the Lobster. By Dr. M. P. Erdl. Munich, 1843. 



To those who are acquainted with the elaborate researches of 

 Dr. Rathke upon the development of the river Cray-fish, the present 

 treatise will be one of peculiar interest, from its fui'nishing a parallel 

 history in respect to another species of the genus Astacus so closely 

 allied to the above. It would be impossible however, within the 

 limited space allotted in our Journal, to do justice in an abstract to 

 the masterly and lucid details which our author has given us upon 

 this subject ; their general bearing will be best understood by a 

 careful perusal of the work itself, and a comparison of the text with 

 the four beautiful coloured quarto plates, illustrating chiefly the early 

 periods of embryonic existence, i. e. prior to the exclusion of the 

 young lobster from the e^g; periods which, according to Dr. Erdl, 

 have been hitherto passed over in silence by most writers. We shall 

 be content therefore with noticing those facts only which will be best 

 appreciated by the general reader. 



" It is well known that the eggs of crabs, when they have issued 

 from the sexual orifice of the female, become attached to her sub- 

 abdominal false legs, the inner and outer edge of which chiefly are 

 fringed with hairs placed near to each other like the teeth of a comb. 

 The fastening of the eggs takes place in the following manner : — 

 "While the eggs are being laid, or even before they reach the external 

 sexual aperture in such crabs as Maja, where the oviduct is very 

 short, they liave to pass the orifice of a thick sac opening into the 

 lowest part of the oviduct, and which is enlarged at the time of lay- 

 ing and filled with a tenacious slimy fluid. At the very instant in 

 which the eggs are propelled through the oviduct, this slime is pressed 

 out of the sac over the eggs, so that they come out covered with it. 

 In other Crustacea (Astacus) this sac is wanting, and the oviduct 

 appears large enough to furnish a sufficient quantity of viscous fluid 

 from its internal surface. Upon coming in contact w'ith the water 

 the slime immediately hardens and forms a covering round each egg, 

 which, by the contraction of the tail upon the false feet and their 

 hairs, become pressed together, and adhere not only to the extremity 

 but the whole length of the latter. The tail is again extended after 

 the eggs are laid and attached, and they then sink down slightly by 

 their own weight, so that the slime is lengthened out and thus forma 

 a cord passing from the hairs to the ova, where it diverges to be con- 

 tinued over them as an external envelope. The cord being hardened 



