New Forms of the Hemichordata. 159 



like, and functions as an organ for conveying the eggs from the 

 nephridial opening to the brood chamber as described below. 



Tentacles. — The number of tentacles in specimens with eggs, and 

 therefore probably full grown, is about 90, though much fewer 

 were observed in others with rejuvenating (?) heads and in small 

 specimens. 



The number of coils of the lophophore when contracted (in 

 sections) was at most one and a half on each side, and, when 

 fully extended, one, that is, in the circle of tentacles, the course 

 from a point in front of the middle of the mouth to a corresponding 

 point behind, was about circular with a slight re-entering curve in 

 which the eggs were lodged (vide fig. 1). The coils were flat, that 

 is, not in a turreted form as described in P. australis (2) and P. 

 bushii (7). 



Septa. — A transverse septum exists in P. capensis, but it is not of 

 the same character as in P. australis (2). In the latter it is com- 

 posed of a homogeneous dense matrix with embedded cells and 

 spaces lined by cells. This condition, which I have also found in 

 section of P. hippocrepia, may have been brought about by the 

 invasion of the septum by the gelatinous basement membrane of the 

 body wall. In P. capensis only a part on each side and behind 

 is so invaded, the rest of the septum being composed of the closely 

 applied coelomic epithelium of the supra- and infra-septal cavities, 

 so that in longitudinal section near the right or left body wall the 

 septum appears of the character found in P. australis, while in a 

 median longitudinal section the septum is in the form of cells with- 

 out basement tissue. The characteristics of the septum in this 

 respect would probably be of value in specific determination, but it 

 has not been described for most species. 



The mesenteries of the cavity below the transverse septum are of 

 the same character. Gaps, however, occur in them, and the two 

 layers are not always evident. In the nephridial region of the 

 lateral septa the basement tissue, however, appears. 



Nephridia. — There are two nephridia. In addition to the large 

 opening into the rectal chamber, there is a smaller into the lateral 

 chamber. The rectal opening is continued down the mesentery for 

 a considerable distance, as described in P. australis, and other 

 species. 



Circulatory System. — Some of the details of the course of circula- 

 tion were made out by examination of sections, but chiefly by 

 observations on the living animal. They showed that the circulation 

 was apparently different from that of P. australis (2). 



In sections, the afferent vessel was seen to be divided into two 



