ON A NEW SPECIES OF PHYMOSOMA. 



ARTHUR E. SHIPLEY, M.A. 



Christ's College. 



During a visit to the Bahama Islands, Mr Weldon was fortu- 

 nate enough to find three specimens of a large brown Phymosoma, 

 whilst investigating the Fauna of the Bimini lagoon. He came to 

 the conclusion that these specirnens belonged to no described 

 species of Phymosoma, and was good enough to hand them over 

 to me for description. I propose to call this species Phymosoma 

 Weldonii. 



The length of the three specimens varied between 3'5 cm. 

 and 3 cm. ; their bodies are plump and slightly curved. The 

 ground colour of the preserved specimens is light yellow, but this 

 is modified over the surface of the body by dark brown papillae. 

 In all three specimens the introvert is retracted, and in this condi- 

 tion is about 1 cm. long. The papillae are of two kinds, flat, brown, 

 rectangular, low elevations on the skin of the trunk, and conical, 

 elevated protuberances of a light colour on the introvert. 



No hooks or traces of hooks were found on the introvert. 



At the base of the introvert, just behind the head, is a well- 

 developed collar, such as I have described in detail in Phymosoma 

 varians. 



The mouth is surrounded by a vascular lip, which at the dorsal 

 middle line is continuous with the base of the lophophor. The 

 latter is in the shape of a double horseshoe, and is composed of 

 from 70 to 80 tentacles. 



There is nothing to call for remark in the arrangement of the 

 internal organs, with the exception of the fact that there are only 

 two retractor muscles. Such an arrangement is only met with 

 elsewhere in Ph. Rujppellii from the Red Sea. The absence of 

 hooks and of any traces of them is striking, but it occurs in five 

 other species out of a total of 28 described. 



Habitat ; the Bahama Islands, Bimini lagoon. 



