268 RECORD OF CURRENT RESEARCHES RELATING TO 



careful to point out that the longitudinal trunks might very well be 

 muscular, and Schiefferdecker has described the muscular elements 

 in these forms as consisting of long delicate spindles, which pass at 

 either end into very fine processes. True epithelial cells were only 

 observed on the sheath of the proboscis. 



Natural History of the Orthonectida. — In connection with the 

 last note on this subject,* it is necessary to observe that in a short com- 

 munication I Metschnikofif says that his species Bhopalura Giardii 

 must fall, as it is clearly identical with the B. opMocomce and 

 (Mac)Intos}iia gigas of that author. He bases his view of the generic 

 and sjjecific identity of the two forms just mentioned on the constancy 

 of zoosperms in the smaller form, on their absence in the larger one, 

 and on the complete similarity in character of these elements with 

 the " ovarian cells " of Bhopahira. The sperm-elements are asserted 

 to have a long flagellum, and not to be bacterioid, as stated by Giard, 

 and the so-called muscular bands are never observed in the female, 

 nor is there the difference in rapidity of movement between 

 " Bhopalura " and " Intoshia " that should be expected from the absence 

 in one and the presence in the other of such muscular structures.| 



Echinodermata. 



The Elasmopoda— a New Order of Holothiiridea.§ — Sir C. Wy ville 

 Thomson, on looking over the Holothuridea of the ' Challenger ' 

 Expedition, recognized the resemblance of a large number of the deep- 

 sea species to Elpidia glacialis, a form found by Dr. Hjalmar Theel at 

 a depth of 150 fathoms in the Kara Sea in 1875, who was accordingly 

 asked to undertake the description of the material belonging to the 

 class. As the result of his examination, Dr. Theel recognized over 

 200 species, half of which are new to science, and of these the greater 

 number from the deep-sea are related to Elpidia. The group, 

 enlarged to such an extent and presenting so many marked 

 peculiarities, quite revolutionized the fades of the Holothuridea, and 

 asserted itself as an order of value equal at all events to that of the 

 Pedata and Apoda, and for this order Dr. Theel proposes the name 

 Elasmopoda. 



Order : Elasmopoda (eXaww, to move). Body distinctly bilateral. 

 Ambulacra well defined. The lateral ambulacra of the trivium 

 bearing large, slightly retractile pedicels, disposed either in a single 

 row, or sometimes in two rows, along each side of the ventral surface, 

 and sometimes with another series of larger highly-elongated not 

 retractile processes placed externally and above the pedicels ; pedicels 

 of the two lateral ambulacra symmetrically arranged, being more or 

 less distinctly opposed across the ventral surface. The odd ambu- 

 lacrum naked or very seldom with a few rudimental pedicels. Bivium 

 provided with very long not retractile processes, often disposed in one 

 or more rows along each of its ambulacra and more or less distinctly 



* This Journal, ante, p. 86. 



t ' Zool. Anzuiger,' ii. (1879) p. 618. 



X This note should have been inserted after the tliird paragraph of p. 87. 



§ 'Nature,' xxi. (1880) p. 470 (11 figs.). 



