34 NEW INVERTEBRATA FROM 



Male and female oroaiis are found in diiferent individ- 

 iials. The ovaries are orange colored; the spermaries, 

 white or cream colored. Artificial fecundation Avas accom- 

 plished by methods similar to those already described in 

 my paper on the development of Echinarachnius. Sexual 

 organs are capable of fertilization iu the month of March. 



The ovum of Ophiothrix has a central, more opaque and 

 a peripheral trausparent zona radiata, as in Ophiopholis. 

 Eggs fertilized at 12 m. passed into a four-celled stage at 

 8 r.M. and into a ciliated gastrula at 9 a. m. of the fol- 

 lovviug day. All the successive stages in the infolding of 

 the blastoderm to form the gastrula were observed and 

 they were found to closely resemble those which I have 

 elsewhere figured for Ophiopholis. My observations sup- 

 port those of Balfour and do not agree with those of 

 Apostolides. 



ANNELIDA. 

 Sabellaria Caltfornica sp. no v. 



(PLATE VII, FIGS. 3, i.) 



The inroads of the sea have worn the soft rock of Punta del 

 Castillo into caverns on the roof of which many honey- 

 comb-like formations of sand and fragments of shell are 

 found. This iucrustation,lxire at low tide, forms in places 

 a continuous mass several feet across and from a foot to 

 two feet in thickness. It is a solid aggregation of worm 

 tubes, the openings of which are found to be closed by 

 the conical operculum of a Sabellaria. A fragment of 

 this iucrustation is represented on Plate vii, fig. 3. 



The mass is easily crushed, is very fragile, and com- 

 posed of particles of shells and grains of sand cemented 

 loosely together. These worm tubes can be easily cut 

 from the mass and the bodies of the Sabellaria readily ex- 



