BOTANY OF THE UNITED STATES. 79 



his own part of the book. Like all his other works, it shows the combi- 

 nation of skill in treating his subject with perfect familiarity with the 

 details. No living botanist is so competent to describe the plants of North 

 America ; and no one has done more than he to illustrate the flora of his 

 country ; nor is any one so unceasingly at work, and few so prolific with the 

 pen. Would that we could add that all the works of our excellent friend 

 were brought to a like happy terminus as the present ; and, specially, that 

 the " Flora of North America" (Torrey and Gray) were among the num- 

 ber. To the deep regret of all botanists, that invaluable work, commenced 

 in 1838, after reaching Composite in 1843, seems to have been cushioned 

 by its authors for the last thirteen years. 



W.H.H. 



Preliminary Notices of the Invertebrate Animals collected in the 

 United States Expedition under Captain John Rodgers to the 

 Southern Pacific Ocean. By W. Stimpson. Part I. (From the 

 Proceedings of the Academy of Natural Sciences of Philadelphia, 

 February, 1857.) 



In the twelve pages before us we have, printed in small brevier type, a 

 list of all the species of the Turbellaria Dendroccela, which were taken in 

 the South Pacific Expedition sent out by the United States. This 

 class of animals is very nearly allied to the Annelida ; in fact, the one class 

 merges into the other by almost insensible gradations. We have but few 

 representatives of it in our British Isles, but the common Elasmodes 

 (Planaria) flexilis will serve as a good example. Mr. Stimpson applies 

 the name Dendroccela to the whole tribe, in this following Diesing. He 

 also divides it into two sub-tribes, Digonopora and Monogonopora. Ap- 

 pended to the list of species found we have descriptions of fifty-two new 

 ones ; many of them, we remark, taken " in portu, Hong Kong." The 

 genus Planaria Mull, is placed under the sub-tribe Monogonopora (apertura 

 genitalis unica), whereas the Planaria of Dalyell, Gosse, and others, repre- 

 sented by flexilis, stagnalis, &c, is merged into the genus Elasmodes of 

 LeConte, and placed under the sub-tribe Digonopora (aperturae genitales 

 dua3. We trust that we shall have the pleasure of noticing the various 

 parts of these most valuable Notices as they appear, and that when com- 

 plete we may be able to give our readers a critical review of them. The 

 author proves himself to be quite conversant with all our lately published 

 British works on this subject ; and we might, in conclusion, notice that the 

 Leptoplana tremellaris of Oersted is not thought by him to be identical with 



