312 Analyses of Books. [api*l 



zoophytes.* In the Tubular ia indivisa, a current of particles was 

 seen within its tube, which, in its combined and steady flow, resem- 

 bled the circulation in plants of the genus chara. The general 

 course of the stream was parallel to the slightly spiral lines of irregular 

 spots on the tube. Between the stomach and the mouth a remark- 

 able action was observed. The mouth became swollen by a flow into 

 it from the stomach, which continued for about a minute. The con- 

 tents of the mouth were then squeezed back into the stomach, and 

 during this reflux the connecting orifice was seen distinctly open, and 

 it continued so till the stomach became nearly empty. The orifice then 

 closed gradually, preparatory to the effort of forcing the fluid back to 

 the stomach. Two currents were continually going on both in the 

 mouth and stomach, one flowing down the sides and an opposite one 

 in the axis. 



These observations were made by a microscope which magnified 

 100 times, and drawings were taken by a camera lucida slid over the 

 eye piece. 



In the Sertularia pluma Ellis, a current was observed following 

 in the channel backwards and forwards through the main stem and 

 lateral branches of a pluma, and might be compared to the running 

 of sand in an hour glass, five ebbs and flows occupying 15 J minutes. 

 When the connexion of a plume with the root was interrupted by 

 bending its stem, the stream running down the middle was observed to 

 continue its flow up one of the lower and stronger lateral branches, 

 and then to return down that branch and up the main stem. The 

 section of a stem made below the commencement of the side branches 

 exhibited a small stream apparently followed by viscid matter. Ca- 

 volini first observed this, but no subsequent writer has noticed it. In 

 Sertularia pumila, an irregular motion was noticed in the stomach 

 and mouth, and likewise, but not distinctly, in S setacea, dichoma, 

 and in species of Campanularia. 



In a small Ascidia occurring on the conferva elongata, circula- 

 tion was observed through the transparent coat, the particles of the 

 blood not exceeding 00025 inch in diameter. The blood enters the 

 heart from the peduncle, the ventricle contracts in the middle and 

 drives the fluid into the branchial organ, and into a network of vessels 

 over the stomach and intestines. After the circulation has gone on 

 for a while, the pulsations become fainter and gradually cease when 

 the current is reversed. A Polyclinum exhibited also internal mo- 

 tions. 



In Cellularia and Flusira none of the internal currents which 

 ill the sertulariae connect the different parts of the zoophyte were ob- 

 served, nor was any circulation detected. Each animal is enclosed 

 in its cell, and sends out its mouth and arms through a valve. A 

 short sheath precedes them, from whence the arms rise straight to- 

 gether, and then open to a funnel-shaped figure of beautiful regu- 

 larity, serving probably to draw food to the mouth by currents. Be- 



* The useof this term has been much reprobated by Lamarck, but notwithstand- 

 ing his censure it still continues to be employed by many distinguished naturalists ; 

 and it is sufficiently expressive of a class oi beings whose nature is st 11 involved 

 in great obscurity. — Edit. 



