14 C. P. JENKIN. 



The triradiates in the oscular collar are similar to (c), but have longer 

 paired rays. 



The fringe consists of : — 



(g) Minute oxea, 120 m long x 1 fi to 2 /j. thick. 



Family GEANTIIDAE Dendy. 

 Leucandra Dendy. 



The collection contains five new species and one new variety belonging to 

 this genus. 



The genus Leucandra, as defined by Dendy, is too comprehensive and needs 

 subdivision. The minute structure of the species belonging to the genus has not been 

 sufficiently examined ; the wide variations in the development of the mesoderm, and 

 also the arrangement of the incurrent and excurrent canals, require investigation. 

 Some notes on these points are contained in Part III. 



Want of accurate knowledge about the structure makes the classification of the 

 species in this genus difficult and uncertain. The species Leucandra frigida, Leucandra 

 brumalis, and Leucandra gelatinosa can only be considered as provisional ; Leucandra 

 cirrata and Leucandra hiberna are more definitely diff"erentiated. 



Leucandra primigenia, H. var. leptoraphis. 

 (Plate XXIX., Figs. 33-34.) 

 Leucetta primigenia Haeckel (3), Vol. II., p. 118. 



There are two specimens of this new variety in the collection. The larger consists 

 of an irregular mass of anastomosing branches (Fig. 33), dirty white in colour as 

 preserved in spirits. The surface is mostly smooth, but in places is more open or 

 spongy in structure. The branches have a very small gastral cavity running down 

 them, ending in inconspicuous closed oscules. It agrees with Haeckel's description of 

 Leucetta primigenia [var. isoraphis), except that the spicules are very much slenderer. 

 Haeckel gives the ratio of length of arm to thickness as 10 to 12. Polejaeff", for the 

 ' Challenger ' specimens of Leucetta primigenia, which he calls Leucetta fruticosa, gives 

 the ratio 12 to 15. The new variety has the ratio 25 to 40. The spicules are 

 shown in Fig. 34, with one of the ' Challenger ' specimens of Leucetta primigenia for 

 comparison beside them. Haeckel does not describe the alate oscular spicules, which, 

 in the new variety, difi"er widely from the normal spicules, as will be seen from the 

 figure. These spicules lie with the basal rays circumferentially round the oscule, and 

 not, as might have been expected, symmetrically. 



PolejaefFs species, Leucetta dura, cannot now remain, since it is only based on the 

 existence of an oscule which was supposed not to be always present in Leucetta 

 microraphis. 



