ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
39 
Rotatoria. 
Two Xew Rotifers.* * * § — Mr. J. E. Lord figures and describes two 
new species of Rotifers found by him in Yorkshire : — Taphrocampa 
nitida and Ccdlidina cataracta , the latter characterised by strongly 
marked longitudinal ridges and eight rough spines in a row across the 
back, followed by a deep rounded depression. In this respect it is 
closely allied to Weber’s Gallidina Brycei. 
Varieties of Anursea cochlearis.t— Dr. Robt. Lauterborn gives an 
account of the variations in size and length of spines in this rotifer, 
observed by him for a number of years in the old channels of the Rhine 
near Ludwigshafen. In addition to the type species, he distinguishes 
the following three varieties: — macracantha , with very long posterior 
spine ; Jiispida , covered with minute elevations ; and irregularis , which 
has irregular markings. A. tecta is considered an extreme spineless 
variety of A. cochlearis. 
Lauterborn’s particular question is, whether the variations show any 
relation to the seasonal changes, and he answers it in the affirmative. 
About 2000 individuals were examined. The variations relate to the 
size and structure of the carapace and to the disposition of its plates. 
The varieties known as hispida and irregularis are especially summer 
forms, and the variety tecta is also most abundant in the warm months. 
The same succession of varieties is observed in different localities ; the 
size bears an undeniable relation to the temperature of the water. 
Oogenesis and Maturation in Hydatina senta.J — Dr. Lenssen 
begins his account with the period of ovum-formation. In an individual 
seven minutes old there are four mother-cells, which multiply rapidly 
and form ova, forty or so in three-quarters of an hour, each showing a 
peculiar nuclear cap. The next period is one of growth, which may be 
slow or rapid. The ova are detached and glide on the surface of the 
yolk-gland in the direction of the uterus, increasing in size as they do 
so. In the uterus the process of maturation begins. It seems that the 
parthenogenetic eggs which become females form a division-spindle, but 
do not liberate a polar globule. There is a distinct centrosome. In 
the eggs which become males there is a spherical refractive body in tho 
ovum, and there are at least polar coronas in the maturation spindle. 
In the “ Dauereier ,” which are fertilised six hours after birth, the 
maturation spindle shows polar corome, and there is a vague hint of an 
expelled polar body. 
Ecliinoderma. 
Respiratory Trees of Holothuroids.§ — L. Bordas has made, at the 
Marine Laboratory of Endoume (Marseilles), a large number of observa- 
tions on Holothuria impatiens Gmelin, H. Poli Dclle Chiaje, H. tubulosa 
Gmeliu, and Stichopus regalis Selenka. He succeeded in showing that 
the arborescent organs, which develop as diverticula from the gut, and 
are almost identical with it in histological structure, have at least four 
important functions. As has been generally recognised, they are respi- 
* .Tourn. Quekett Micr. Club, vii. (1898) pp. 75-80 (1 pi.). 
t Zool. Anzeig., xxi. (1898) pp. 597-604 (6 figs.). 
X Tom. cit , pp. 617-22 (9 figs.); La Cellule, xiv. (1898) pp. 421-51 (2 pis ). 
§ Comptes Renrtus, cxjivii. (1898) pp 568-70. 
