44 ZOOLOGICAL COLLECTIONS MADE DURING [Jan. 4, 



circular at the lower end than that of this species ; and the extension 

 of it upward is irregular, there being a part of it which extends at an 

 angle within the valve. 



These differences appear constant in the four specimens oi M.fis- 

 cherianus and the eleven of M. chorus which I have examined. 

 The latter species is figured in Cunningham's • Natural History of 

 the Straits of Magellan^ on a plate opposite p. 155, under the name 

 of Mytilus chilensis. This is not, however, the M. chilensis, Hupe. 

 The largest specimen of M. fischerianus is 1 25 millims. long. 



Mytilus, sp., juu, 



liab. Station?. 



There are two apparently young shells which I cannot identify 

 with any described species. They are remarkable on account of the 

 great breadth, which is about the same as the length. The sculpture 

 too is very curious; it consists of 15 to 20 very thread-like lirae 

 which radiate from the apex to the outer margin. The texture is 

 thin, semitransparent, bluish white ; and the surface is clothed with a 

 thin pale-olive epidermis. 



Mytilus magellanicus, Chemnitz. 

 Uab. Station 3. 

 Pecten patagonicus. King. 



Hab. Stations 1, 2, 3, 6, and Puerto Bueno, 2-7 fathoms, rocky 

 bottom. 



Brachiopoda. 



Waldheimia dilatata, Lamarck. 



Hab. Stations 2, 3, 5, 7, and Cockle Cove, 2-32 fathoms, mud. 

 One of the specimens from Portland Bay is very fine, having a 

 diameter of 50 millims. 



Waldheimia magellanica, Chemnitz. 

 Hab. Stations 2, 5, and 7. 



V. POLYZOA. 



By Stuart O. Ridley. 



(Plate VI.) 



For the systematic arrangement of the species here described, 

 Mr. Hincks's most valuable recent work on the British Marine 

 Polyzoa has been chiefly followed; the key to the generic re- 

 lations of the species is therefore to be found there. I have 

 hesitated to name many new species, preferring in some cases to 

 designate as varieties forms which, were the known variability of 

 recent forms and the number of readily identifiable and largely 

 described fossil ones less than they are, would probably have been 

 set down with little doubt as distinct species. 



