112 ARTHUR E. SHIPLEY. 



Part I. 



Genus Phymosoma. 



Phymosoma Weldonii, n. sp. 



The length of the body is 3*5 cm. in the largest specimen, 

 3'25 cm. in the second, and 3 cm. in the smallest. The greatest 

 width is 1 cm. At the base of the introvert, which was in each 

 specimen retracted, the width is 2 mm. The body has a plump 

 appearance and is slightly curved (fig. 1). 



The ground colour of the preserved specimens is light buff, 

 which is modified by the presence of dark brown papillae ; 

 these are so numerous as to give the animal as a whole a dark 

 brown colour. The papillae are of two kinds (figs. 2 and 3). 



No hooks or traces of hooks can be detected on the introvert. 



The mouth is surrounded by a vascular lower lip, which in 

 the dorsal middle line is continuous with the outer limbs of the 

 lophophore. The latter structure is in the shape of a double 

 horseshoe, the outer semicircle of tentacles corresponding to 

 the lophophore of Ph. varians. In the ventral middle line 

 this outer limb is bent dorsalwards, and thus the second horse- 

 shoe is produced (fig. 5). The lophophore bears a great number 

 of long tentacles, seventy or eighty (figs. 5 and 8). 



Behind the head is a well-developed collar, pigmented on the 

 anterior surface (fig. 5). 



The alimentary canal is tightly coiled, the number of twists 

 being twelve or thirteen (fig. 4). It is supported by a well- 

 developed spindle-muscle, which passes up the axis of the coil, 

 and is attached at one end to the longitudinal muscles of the 

 body-wall in the neighbourhood of the anus, and at the other 

 to the posterior end of the body-wall. The anus is situated 

 at the line of junction of the two kinds of papillae. 



The longitudinal muscles are arranged in ten or twelve 

 bundles in the anterior half of the body ; in the middle of the 

 body there are about twice that number, as each bundle splits 

 into two. These fuse together again at the posterior end of 

 the body. At the base of tlie introvert the usual inversion of 



