New Forms of the Hemichordata. 165 



upwards, stronger than the inhalent current (being more confined). 

 It might be expected that a part or all of this current would also flow 

 out over the anus and nephridial openings by the large space which 

 forms the open part of the horseshoe-shaped lophophore, and, indeed, 

 Masterman (6), who, however, had not the living animal, describes and 

 figures such a current as existing. If the living animal is carefully 

 observed, however, it can be seen that not only does no such current 

 exist, but that there is a current leading inwards not outwards at 

 this aperture, so that it passes first over the two pillar-like sides 

 of the lophophore which are characterised by the special develop- 

 ment of nervous tissue at this place, then over the nephridial open- 

 ings and the anus, and joins the strong exhalent current of the inner 

 circle of the lophophore. Benham (2) has accurately described this 

 patch of nervous tissue, and regarded it as structurally the only 

 approach to an appearance of a sensory organ in Phoronis, but 

 expresses his doubts on account of its proximity to the excretory 

 openings. The existence of such a current of water however, pass- 

 ing in turn over the nervous epithelium, the renal openings and the 

 anus, removes this objection, and renders the case quite similar to 

 that of the current, for instance, in the palleal chamber of some 

 Mollusca, which passes first over the osphradium, then the renal 

 aperture, and finally the anus. It lias been repeatedly observed 

 that the animal seems very sensitive to the condition of the water in 

 which it lives, and I cannot but think that the two special patches 

 of nerve tissue represent a sensory organ similar in function to the 

 osphradium of molluscs, and it may be called for want of a better 

 name the olfactory organ. 



Still another movement may be observed, but with greater diffi- 

 culty. It occurs on the upper part of the body just below the 

 insertion of the lophophore. No current of water was observed, but 

 merely a movement of particles apparently entangled in mucus and 

 in contact with the body. These were slowly carried upwards away 

 from the mouth of the tube. Very small cilia were on occasions 

 observed. This action may account for the fact that no foreign 

 particles, such as might fall into the tube, were found included in 

 its substance where embedded in the stone. 



Eggs, Larvce, Oviposition, Breeding Season, dfcc. — The eggs and 

 embryos are very conspicuous, and could be readily observed mostly 

 within the lateral bends of the inner circle of tentacles though 

 occasionally projecting outside these bends. Those nearest the 

 body were apparently held together by the mucus which is secreted 

 by the glandular part of the lophophoral organ; those near the free 

 ends of the tentacle were further developed, some attached to the 



