6 C. F. JENKIN. 



{(I) The development of tlic gelatinous mesoderm in Lemnndra r/filn/inosa. 



(e) The duplic;ite ovum, apparently a new type of egg cell, in Jfcf/a/ioi/on rarlpilvs. 



JjOoaUt}!. — All the specimens were taken, at variou.s dates, in Winter Quarters 

 and most of them from shallow waters. 



PART II. • 



Description of the Specimens with Definitions of the New Genera and 



Species. 



Grade HOMOCOELA Pol. 

 Family CLATHRINIDAE Minchin. 

 Clathrina primordialis. 

 AscMa primonlMis Haeckel (3), Vol. II., p. It). 



There is one small ])rokeu specimen f)f this species in the collection. In colour 

 it is yellow as preserved in spirits. The spicules agree exat-tly with Haeckel's 

 description. 



Gl.^thrina coriacea. 

 Ascella roriacpn ILieckcl (3), Vol. II., p. I't. 



There are two small broken specimens of this species in the collection. In colour 

 they are yellow, as preserved in spirits. The spicules agree exactly with Haeckel's 

 description. 



Family LEUCOSOLENIID^ Minchin. 



Leucosolenia complicata. 



Leucosolenia complicata Minchin (8), p. M60. 



There are five pieces of sponges of this species in the collection. The spiculation 

 agrees closely with the revised description given by Minchin. 



Leucosolenia discoveryi. 



(Plate XXVIIL, Figs. 12-13.) 



There arc about twenty-five specimens of this nmv species in the collection. 

 Its appearance and habit of growth are admirably .shown in Fig. 12, drawn by Professor 

 Minchin. Its colour is white as preserved in spirits. The oscular tubes in some 

 specimens attain a length of 9 mm. and a diameter (fiatteued) of 1 mm. 



