12 EEPOKT OF THE SECEETARY. 



aud jihy siolo gy of haUclystusailrictila.''^ In the first part are three chapters; 

 the first on "individuality," in which are considered the questions re- 

 lating to "polarity and polycephalism" and "the hydroid and medusoid 

 cephalisms." In the second the thesis that "the type of form is not ra- 

 diate" is defended, and the form is described as "the dorso-ventrally 

 repetitive type." The third chapter is devoted to the consideration of 

 " antero-posterior (cephalo-caudal) repetition," and under the heads of 

 "the scyphostoma and ephyra varieties of the same morph" and "the 

 individuality of Pelagia and Lucernarire." 



In the second part are four chapters, the third to seventh of the en- 

 tire work. In the first (third of the work) are described the "general 

 form and structure," including habitat, habits, form, and size, the pro- 

 boscis, the umbella, and the peduncle. In the second is considered the 

 " organography, including the walls," " the muscular system," " the tenta- 

 cles, the marginal adhesive bodies, or collecystophora," "the caudal ad- 

 herent disc," "the digitiform bodies, or digitali," "the digestive system," 

 "the nervous system," and "the reproductive system." 



In a third are embraced the results of studies of the " embryology," 

 or various stages of growth of the species, including observations on 

 " the egg and the spermatozoa ; " on " a young haliclystus auricula, nearly 

 one-sixteenth of an inch in diameter;" on "a specimen three thirty- 

 seconds of an inch across the umbella;" on "a young specimen one-eighth 

 of an inch across;" on the "special development of a tentacle, a coUeto- 

 cystophore, and a genital sac;" on the "young one-fifth of an inch 

 across;" and on the "young six twenty-fifths of an inch across." 



In a fourth chapter the tissues are considered in a "histology of MU- 

 clystvs aiiricuW^ and in the several parts of the body — that is, "the um- 

 bellar and peduncular walls;" "histology of the tentacles;" "histology of 

 the collectocystophores," (anchors;) "histology of the caudal disc;" 

 and "histology of the digitali" and "the prehensile cysts," (nematocysts 

 and coUetocysts.) 



This enumeration of the chapters and their sections will furnish to 

 the naturalist an adequate idea of the mode of treatment of the subject 

 as well as of the different organs and parts represented in the animals. 

 It will suffice to add that the several parts are treated of in great 

 detail, and are illustrated in eleven quarto plates from drawings by the 

 author. 



The plates for this memoir are in the process of being engraved, and 

 the Avork will be published as soon as the funds of the Institution will 

 permit. We have to regret, since the work was adopted by the Institu- 

 tion, that the author has been called from this life in the flower of his 

 age and the promise of many days of successful devotion to science. 



The next memoir accepted for publication, and which will probably form 

 the whole of the twentieth volume of the Contributions co Knowledge, is 

 by Joseph Jones, M. D., professor of chemistry and clinical medicine in 

 the University of Louisiana. It gives the results of a very extended in- 



