298 



EVENINGS AT THE MICROSCOPE. 



DUMB-BELLS IX HOLOTEVHIA. 



opposite end by two other dumb-bells ; and the structure 

 is complete as you see it. In almost all cases the two 



united globes of these ter- 

 minal elements are fused 

 into one globe, and in not 

 a few instances the ap- 

 pearance is as if these 

 two dumb-bells were but 

 one, bent over in a semi- 

 circular form ; but still a 

 good many specimens oc- 

 cur in which the two dumb-bells can be quite distinguished 

 from each other. The calcareous matter that solders the 

 elements together seems abundant, and has the appear- 

 ance that would be presented if they had been made of 

 solid glass, and united by glass in a state of fusion ; the 

 latter having apparently run together, so as to smooth 

 and round angles and fill up chinks, even where, as is 

 often the case, the globes themselves have only mutually 

 approximated, and not come into actual contact. 



The average dimensions of these oval aggregations 

 may be .004 inch in length, and a little more than .002 

 in width ; but some specimens occur which are a little 

 larger, and others a little smaller than this ; while the 

 irregular plates are sometimes three times the length. 



Some of the more worm-like 

 members of this class have, 

 however, a skeleton composed 

 of pieces imbedded in their 

 skin, of even more remark- 

 able shapes than these. One 

 of these is the CJdrodota 

 violacea ; a native of the 

 southern coasts of Europe. 

 We have indeed a British 

 species of the same genus, a 



^**^~~f^ 



WlIKhL UN IH1KODOTA. 



