ART. 7 



A NEW RHIZOCEPHALAN "PAEASITE — BOSCHMA 



opening. This lacuna is distinctly visible in Figure 3; it denotes 

 approximately the ventral and posterior border of the mantle when 

 not spread out as in the figure. 



Nearly the whole space of the mantle cavity was occupied by the 

 well-developed visceral mass, no eggs or developing larvae being 

 present in the mantle cavity. The visceral mass (fig. 4) possesses a 

 somewhat wrinkled surface, doubtless on account of the pressure of 

 the irregular internal surface of the mantle. The scar of the removed 

 mesentery is visible in the figure, at the left side the posterior part, 

 which lies approximately in the median plane; at the right side of 

 the figure the anterior part of the mesentery, which deviates from the 

 median plane and runs along the right side of the visceral mass 

 toward the mantle opening, is to be seen. 







Figure 6.— Briarosaccus callosus, part of a transverse section a in figure 4, showing one of 



THE COLLETERIC GLANDS. THE CONTENTS OF THIS GLAND HAVE BEEN OMITTED IN THE FIGURE. X 14 



For the study of the internal organs a part of the visceral mass 

 has been cut off. This part, from which a series of sections has been 

 made, is indicated in Figure 4 by the full line. Parts of two sections 

 are represented in the present paper; Figure 6 is a drawing of a part 

 of a section corresponding with the line a in Figure 4, whilst Figure 

 5 is drawn after a section from the region indicated with 6 in Figure 4. 



With the exception of the part surrounded by the line in Figure 4, 

 the visceral mass consists nearly completely of groups of eggs in the 

 ovary; between these groups of eggs numerous smaller and larger 

 muscles are present. As already remarked, the central part of the 



