122 Lesions in Monkey s Brain. Phymosoma varians. [May 16, 



VI. "Appendix to Paper* on Descending Degenerations follow- 

 ing Lesions in the Gyrus marginalis and Gyrus fornicatus 

 in Monkeys." By E. P. France. Communicated by E. A. 

 S chafer, F.E.S. Received April 22, 1889. 



(Abstract.) 



This appendix contains an account (1) of the degenerations which 

 have resulted from lesions of the external motor cortex alone ; (2) of 

 the degenerations which have resulted from lesions involving both 

 this and the gyrus marginalis ; and (3) a comparison between the 

 respective degenerations resulting from lesions of the external motor 

 surface and of the gyrus marginalis. The results tend to show the 

 existence of a differentiation in the pyramidal tract, the whole area of 

 which is involved in degeneration when both external and mesial 

 motor areas have been removed, whereas after removal of one portion 

 only of the motor area, a corresponding part only of the pyramidal 

 tract area degenerates. 



VII. " On Phymosoma varians." By Arthur E. SHIPLEY, M.A., 

 Fellow and Lecturer of Christ's College, Cambridge, and 

 Demonstrator of Comparative Anatomy in the University. 

 Communicated by A. Sedgwick, F.tj.S. Received May 1, 

 1889. 



(Abstract.) 



The following observations on Phymosoma varians were made on a 

 number of specimens brought from the Bahama Islands by Mr. 

 W. F. R. Weldon, of St. John's College, Cambridge. I am not only 

 indebted to Mr. Weldon for the material of this article, but for very 

 valuable suggestions and assistance while carrying on my investiga- 

 tions. 



The Phymosoma is found embedded in soft coral rock. The length 

 of the fully extended specimens averages 5 cm., the greatest diameter 

 about 5 mm. The introvert is equal in length to the rest of the 

 body. 



The Head. — The head bears a crown of tentacles, which are always 

 equal in number, usually eighteen ; they are arranged in a horse-shoe 

 shaped lophophore, which is dorsal to the mouth. The ends of this 

 horse-shoe are confluent with those of a vascular lower lip, which is 

 also horse-shoe shaped ; the crescentiform opening between these two 



* Read March 27, 1889. 



