286 J. H. ASHWOKTH. 



The spermatozoa develop exactly as in Areiiicola (Gamble 

 and Asli worth, 1898, p. 32, and pi. 5, figs. 29—34). The 

 spermagonia fall into the coelom, and after several divisions 

 give rise to spherical or disc-shaped hollow masses of sper- 

 matids. The central cavity of eacli mass contains a small 

 coagulum, tlie remains of the blastophore. 



By what means the genital products escape is difficult to 

 say. The nephridia are much too small to serve as oviducts, 

 as the width of the lumen of the narrow tube immediately 

 following the nephrostome is only about one third the dia- 

 meter of a ripe ovum. It is possible that the spermatozoa 

 escape by means of the nephridia. The escape of genital 

 products has been seen by Danielssen, who observed that 

 one of his specimens extruded eggs through a small rupture 

 in the body-wall which appeared when the animal was 

 strongly contracted. 



19. The Family Scalibregmid.=e. 



The family of the Scalibregmidse was established by Malm- 

 gren (1867, p. 186) to contain Scalibregma inflatum, 

 Rathke, and Eumenia crassa. Oersted, there being only 

 one species of each genus known at that time. Since then 

 other species and genera have been described as allied to the 

 foregoing, and have been included in the family, although in 

 some cases their characters do not agree with those of the 

 original genera in one or more important respects. The 

 classification of this family is therefore at present in con- 

 siderable confusion, and this is further increased by the 

 almost inextricable entanglement of the three principal 

 genera — Scalibregma, Eumenia, and Lipobranchius. 

 The position is rendered more difficult by the fact that some 

 of the species of these genera have been only briefly de- 

 scribed, and are known only from the external characters of 

 a single specimen, and this sometimes a mutilated one. 



The original description of Scalibregma by Rathke 

 (1843, p. 182), and of Eumenia by Oersted (1844, p. 99j, 



