ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 657 



climb up these. The respiratory function is perhaps the primary one, 

 and a sensory function is indubitable, but there can no longer be any 

 denial of a considerable locomotor role. Thus another of the dis- 

 tinctions between Ophiuroids and Asteroids disappears. 



Ccelentera. 



American Hydroids.*— C. C. Nutting has completed the second part 

 of his magnificent monograph on American hydroids. It deals with 

 the Sertularida3, and it maybe noted that while not more than 20 species 

 of Sertularians from American waters had been previously mentioned 

 in any one publication, the author has found no fewer than 130 species 

 which should be included in the American fauna. More than 30 new 

 forms have passed through his hands, and many others have been dis- 

 covered in scrutinising foreign publications. 



Medusae of the Bahamas. f — A. G. Mayer gives the results of an 

 expedition to the Bahamas. The medusa fauna of this region is poor 

 compared with that of the Tortugas, Florida, the number of species 

 found in the two regions being forty-three and ninety respectively. 

 These differences in two regions upon the same latitude and only 300 

 miles apart the author correlates with different physical conditions, e.g. 

 relation to the Gulf Stream. The paper gives a detailed description of 

 all the forms found, as well as notes on the post-embryonic development 

 of Cabaia and Olindias, from which it appears that Gonionemus, Gubaia, 

 Vallentinia, OUndioides, and Olindias, are closely related genera which 

 may be grouped into one family, the Olindiadre. Observations were 

 made on the phenomenon of asexual budding. In Eucheilota paradoxica, 

 the only known Leptomedusa producing an asexual generation of medusae 

 by a direct process of budding, the daughter-medusae are derived from 

 both endoderm and ectoderm of the gonad of the parent. Two new 

 species have been established, one of which, Parvanemus degmeratus, 

 is the most degenerate free-swimming hydromedusa yet described. It 

 lacks tentacles, sense-organs, and peripheral vascular system. The velum 

 is exceptionally large and provided with powerful muscles ; the medusa 

 swims with great activity, but is short-lived. 



Regeneration and Non-Sexual Reproduction in Sagartia davisi.J 

 Harry Beal Torrey and Janet Ruth Mery describe in this sea-anemone : 

 (1) aboral-oral fission by constriction and rupture, with subsequent 

 regeneration ; (2) a strikingly irregular rupturing-process, which appears 

 to differ from the basal fragmentation of Metridium, only in so far as 

 each fragment retains a bit of the oesophagus and a few tentacles ; and 

 (3) the rare occurrence of aboral-oral division by constriction, which 

 was never seen completed in a normal individual. 



The authors also discuss the causes of fission. Fission of the first 

 two types (1 and 2) depends to such a degree upon active movements 

 of different areas of the foot disk in opposite directions that the idea 



* Smithsonian Institution, Special Bulletin (1904) 325 pp., 41 pis. 



t Mus. Brooklyn Inst., i. (1904) pp. 1-33 (7 pis.). 



X Univ. California Publications (Zoology) i. No. 6, pp. 21 1-226 (7 figs.). 



