" actiimla " without going through a " planula " stage, is not 

 alluded to, the plauula stage being given as a stage of all Hy- 

 droids (p. 66). On page 336 " Bidelphia " is used where 3Lmo- 

 delphia is intended. The five diagrammatic figures on p. 225, given 

 to illustrate birds (fowl), would serve better for mammalian 

 embryology. The lists of works given at the end of each chap- 

 ter are very incomplete and unsatisfactory, many of the latest and 

 most important books being omitted from most of them. Thus 

 under Hydroids the works of Hincks aud Allman, both of which 

 contain much of importance on embryology, are omitted. The 



magnificent treatise on Tubularians by the latter i 

 of the most important hitherto pub" 



of Hydroids. The recent extensive work ( 



nportant hitherto published, both for the embryology 



Nemerteans by Mcintosh is not mentioned, though 

 embryology of the group. Cobbold's works are only once 

 alluded to, and are not mentioned under those groups of Helminths 

 upon which he has done the most. The very valuable works 

 of G. O. Sars on various Crustacea, including the discovery of 

 the very remarkable phenomena in the embryology of Cladocera, 

 are not'referred to. Most of these are works written in English, 

 and should be well known to the author of a work on embryology. 

 Certainly references to such works would have been more useful 

 for most of his readers than those that he gives to special papers 

 in the German and liussian periodicals, which are generally inac- 

 cessible, however valuable they may be. In spite of these defects 

 the book will doubtless prove to be a very useful one, there being 

 no other work in English covering the same orround. "*'• 



4. On some RemarkaUe Forms of Animal Life from the great 

 deeps off the Norwegian Coast. 11. Researches on the Structure 

 and Affinity of the genus Brisinga, based on the study of a new 

 species, Brisinga coronata ; by Geokge Ossiak Sars, (Univer- 

 sity-Programme for the last half-year, 1875. Christiania). — In this 

 vubiable memoir, which is illustrated by seven excellent plates. 

 Professor Sars has given a detailed description of the anatomy^ 

 physiology, and development of the genus Brisinga.^ perhap" 



> Echinoderms in general, ai 

 the relation of Echinoderms to the Annelids. He regards h 

 singa as the most generalized form of star-fish, and consequent 

 of Echinoderms, and supposes it to be one of the little-modin 

 survivors of a primitive type from which the other iornis 

 Echinoderms have descended. It has affinities to the most ancie 

 fossil starfishes of the Palaeozoic rocks {Frotaster, etc.) 



The existence of a genuine vascular system, distinct from t 

 general ])erivi8ceral cavity and its extensions, is denied both in t^ 

 case of this genus an ' '" ' " ' '"' 



