656 SUMMARY OF CURRENT RESEARCHES RELATING TO 



found fifteen species of Rotifers, four of which he erroneously describes 

 as new. The new names with which science has been burdened are the 

 following : — Gastropus Cretensis (= Notops hyptopus), Notops falcipes 

 (= Furcularia forficula), Mastigocerca Bland (= Diurdla Stylata, ac- 

 cording to Jennings' new nomenclature), Cirtopus inermis (= Diurella 

 Dixo n-Nuttalli) . 



New Rotifer of Genus Drilophaga.* — P. de Beauchamp figures and 

 describes Drilopliaga Delagei, sp. n., which he found living parasitically 

 on the common fresh-water leech HerpobdeUa octoculata, near Paris. It 

 is distinguished from D.fucephalus, of Vejdovsky, the only previous 

 representative of the genus, by its shorter .and broader body, devoid of 

 annulations, and its shorter toes. 



Eciunoderma. 



New Gonad in Holothurians.f — G-. Polara finds in Holothnria 

 tubulosa and H. poll that a group of germinal cells persists at the side of 

 the ordinary genital organ, and gives origin to several genital caeca 

 which are perhaps used to replace those which have liberated their 

 sexual products. The cellular strand in question is regarded as 

 analogous to the genital strand in Ophiuroids and Asteroids and to the 

 " dorsal organ " (" genital stolon," " organo assile ") in Crinoids. 



Palseodiscus and Agelacrinus.J- — "VV". K. Spencer has investigated 

 the structure and affinities of these two rare but very important 

 Palaeozoic Echinoderms, using the sectioning method. The fossils were 

 ground at uniform distances of T V mm., and each successive surface 

 photographed. From tracings of the photographs wax models were 

 constructed. On the results of these investigations views are brought 

 forward as to the relationships of some of the groups of Echinoder'ma. 

 Thus : " We must conclude, therefore, that whilst a double series of 

 plates, namely, an outer series peculiar to the Echinoid, perhaps derived 

 from the adambulacrals of Asteroids, and an inner series homologous 

 with the plates of an Asteroid, occur in the ambulacrum of all the 

 Echinoids, a complete double series occurs in PaJ ceo discus, which is 

 therefore entitled to be placed at the base of the Echinoid stem. It is 

 not alone in the structure of the ambulacra that Palaodiscus shows 

 itself to be the most primitive of Echinoids, for we have seen that the 

 inter-ambulacral areas present many ideally primitive Echinoid struc- 

 tures. That the transition must have been from Asteroid to Echinoid, 

 and not vice versa, the possession of a lantern of Aristotle by the latter 

 forms is quite sufficient proof." 



Function of Tube-Feet in Ophiuroids.§ — Hj. Ostergren has made 

 the interesting observation that representatives of various families of 

 Ophiuroids, e.g. Amphiura chiajei, Ophiopholis acideata, and Ophiura 

 albida, can use their tube-feet to adhere to vertical glass plates, and can 



* Bull. Soc. Zool. de France, xxix. (1904) pp. 157-60 (3 figs.), 

 t Anat. Anzeig., xxviii. (1904) pp. 33-7 (4 figs.). 

 \ Proc. K. Soc. London, lxxiv. (1904) pp. 31-46 (1 pi. and 12 figs.). 

 § Biol. Centralbl., xxiv. (1904) pp. 559-65 (2 figs.). 



