6 C. F. JENKIN. 



(d) The development of the gelatinous mesoderm in Leucimdra gelatinosa. 



(e) The duplicate ovum, apparently a new type of egg cell, in Hegapogon raripilvs. 



Locality. All the specimens were taken, at various 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. 

 J?AMILY CLATHKINIDAE MINCHIN. 



CLATHRINA PRIMORDIALIS. 

 Ascetta primordMis Haeckcl (3), Vol. II., p. 1G. 



There is one small broken specimen of this species in the collection. In colour 

 it is yellow as preserved in spirits. The spicules agree exactly with Haeckel's 

 description. 



CLATHRINA CORIACEA. 

 Ascel/a coriacea Haeckel (3), Vol. II., p. 24. 



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. 860. 



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

 agrees closely with the revised description given by Minchin. 



LEUCOSOLENIA DISCOVERY!. 

 (Plate XXVIII., Figs. 12-13.) 



There are about twenty-five specimens of this new 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 (flattened) of 1 mm. 



