Prof. Leuckart on a Sucker-like Apparatus in the Daphniadse. 445 



Cyclostiyma Griffithii. 



Leaves in alternate whorls, 40 in each whorl ; whorls less than 

 ^ inch apart. Divergence = -fa. Stem 2'2 inches in diameter 

 (flattened). The leaves of the whorls are rendered oblique to 

 the transverse axis by distortion ; and where oblique, there are 

 6 leaf-intervals to the inch; but where they run across the 

 stem in their natural position, there are 9 to the inch. 



I have much pleasure in naming this species after Sir Richard 

 Griffith, in whose Yellow Sandstone territory many specimens 

 of it occur, and, by their general analogy to the Carboniferous 

 *Lepidodendra, vindicate the propriety of considering, as he has 

 done, the sandstones and conglomerates among which they 

 are found as the natural base of the Carboniferous system of 

 Ireland. 



XLVII. On the Occurrence of a Sucker-like Adhesive Apparatus 

 in the Daphniadse and allied Crustacea. By RUDOLPH 

 LEUCKART*. 



[With a Plate.] 



DURING my residence at Nice in the spring of 1853, 1 observed 

 a small Entomostracan of the group of the Daphniadte, which, 

 notwithstanding its similarity to Polyphemus, Miill., belonged, 

 from the formation of its large antennae and of its abdomen, to 

 the genus Evadne, Lov. I regarded it as new, and called it 

 Evadne polyphemo'ides. (Similar species, but differing in the 

 number of joints in the large antennae, have been described by 

 Dana under the name of Polyphemus brevicaudis, and also by 

 Liljeborg under that of Podon intermedius, Kroy.) The same 

 animal has since been seen and investigated at Heligoland by 

 Pagenstecher and myself. 



The following characters may be given to distinguish my 

 species. The legs gradually become shorter and more closely 

 approximated posteriorly. Instead of the long and slender ter- 

 minal setse, the two middle legs bear two short and thick hooks 

 with the inner margin plumose. The secondary appendage of 

 the last pair of legs is almost obsolete. The lower vitreous 

 cones of the enormous eye are separated from the rest by a space, 

 and are considerably shorter than the preceding ones ; the last 

 of all are also of a different, pyriform shape. 



What most tended to fix my attention on this little animal was 

 an unmistakeable, large, round sucking-disk (PL XVI. B. fig. 8), 



* Translated by W. S. Dallas, F.L.S., from Wiegmann's Archiv, 1859, 

 p. 262. 



