52 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Total Regeneration of Bryozoa.* — G. M. It. Levinsen reports tliiit 

 in some species of Bowerbanhia and Merribranipora, in Valkeria urn and 

 Cribrillina labiata sp. n., and in some other cases, the whole individual is 

 regenerated from the endosarcof the stolon. The zoecia reproduce their 

 polypide a certain number of times, then the zoecium falls off, and the 

 whole individual is replaced from the scar. 



Genus Tubucellaria.f — A. W. Waters gives a brief account of 

 the species of this genus, in which a description of a new form, 

 T. Zanzibar iensis, is included. Some notes are given upon the ovicells, 

 which appear to differ considerably in structure in different Bryozoa. 

 It is suggested that in the present genus the shape of the opening of the 

 ovicell " seems to be a specific character." The so-called " diminutive 

 polypide " in the ovicellular zocecia is shown to be derived from the 

 substance of the ordinary form. 



Rotifera. 



New Marine Rotifera. $ — Carl Zelinka, in a work of considerable 

 magnitude, describes two new species, Synchceta atlantica and Rattulus 

 henseni, as occurring in great abundance in a certain limited area of the 

 Atlantic Ocean, and which were collected by the German Plankton 

 Expedition of 1889. The area inhabited by these two Rotifers, and 

 these two species only, lies in latitude 60° 17' N., and between longitude 

 14° and 30° W., or about midway between the northernmost coast of 

 Scotland and the southernmost point of Greenland. A few more speci- 

 mens of the same two species were obtained near Bermuda, and then, 

 with the exception of a single dead lorica of a Colurus (or Monurd) 

 obtained in a haul near Ascension, no more Rotifers at all were en- 

 countered in any other parts of the Atlantic Ocean, which was crossed 

 three times. 



The fine-plankton net was lowered to a depth of 400 m., and the 

 richest catch of Synchceta and Rattulus in the above-named area was 

 obtained in lat. 29° W., and contained, by Henson's method of counting, 

 as many as 364,352 Synchmta and 44,500 Rattulus to every column of 

 water having a surface area of • 1 sq. m. (about 1 sq. ft.) and a depth 

 of 400 m. A vast number of floating eggs of these Rotifers were 

 obtained at the same time. The fact that Rotifers occur at such 

 great depth was not known before, and the barrenness, as regards 

 Rotifera, of the rest of the Atlantic Ocean is certainly very remarkable; 



The author finally gives an elaborate review and list of all known 

 marine and brackish-water Rotifera, 156 in number, and discusses the 

 question of the origin of this marine fauna. 



Echinoderma. 



Luminosity of Amphiura squamata.§ — Irene Sterzinger finds that 

 the luminous organs of this Ophiuroid are at the tips of the tube-feet. 



* Oversigt k. Danske Vidensk. Selsk. Fordhandl., 1907, pp. 151-9 (1 pi.), 

 t Journ. Linn. Soc, xxx. (1907) pp. 126-32 (2 pis.). 



% Plankton Expedition der Humboldt-Stiftung, 1889, ii. (Kiel, 1907) pp. 1-79 

 (3 pis.). § Zeitschr. wiss. ZooL, lxxxviii. (1907) pp. 358-84 (2 pis.). 



