428 - ZOOLOGY. 



'wliieb Las its exceptions, bbwever, though they are rare. In early life, 

 for example, the Alciopiils are parasitic in the ctenophorous ccelenterates, 

 but later become free. But recently Dr. J. W. Sprengel, at Naples, 

 %vhile examining specimens of BonelUa (a genus of Gephyrean worms), 

 <letected in their coelom orange-colored cord-like bodies, which mani- 

 fested lively movements, which proved to be polychajtous worms. These 

 were about 10 centimeters long and a millimeter wide, and had about 

 200 segments ; " the maxillary apparatus was rudimentary, and there 

 were only three small teeth in the upper jaw." The form has been 

 named by Dr. Sprengel OUgognathus BonelUw, and referred .to the 

 fauuly of Lumbriconereids. An elaborate description has been pub- 

 lished, with illustrations. (J. E. M. S. (2,) v. 2, pp. 190, 191.) 



Xatatory Bladders in Annelids. 



Certain Annelids may be found floating passively on the surface of 

 the water, and one of such species — the Hesione sicula — was observed 

 by Dr. H. Eisig to emit air-bubbles both from the mouth and anus. 

 Dr. Eisig sought to ascertain the rationale of such phenomena, and his 

 investigations were rewarded by the discovery of a viscus that had 

 apparently been overlooked in the Annelids. In Hesione were found 

 two contractile ai)pendages, which communicated with the intestine, 

 and which might be either distinct bladders or inconsiderable diver- 

 ticula, according to their distension or collapse. These parts are di- 

 verticula of the fore stomach, and are regarded as probably arising from 

 the endoderm. Air-bladders were found to be developed in representa- 

 tives not only of the family Hesionidte, but also among the Syllidfe, but 

 not universally. Their absence or atrophy, when not developed, has 

 been supposed to be due to the assumption of the function of respiration 

 l\v the skin; for although the bladders in question serve to float the 

 animal, such office is merely secondary, and not their principal function. 

 Their primary purpose is supposed to be respiratory. They were never 

 found to contain anything except a gas and a clear fluid, which could 

 be taken in or discharged voluntarily by the animal. The so-called air 

 was not atmospheric, and was supposed to be secreted by the stomach, 

 and probably to be oxygen; enough could not be secured to make a 

 •chemical analysis. Although, as already remarked, the organ with its 

 functions has previously been unnoticed, it was known — e. r/., in the 

 Syllidiie — as the "T-shaped glands." 



Worms as Earthmalcers. 



The common earth-worm comes within the cognizance of the ordinary 

 observer cliietiy as a useful bait to be impaled on a hook and thus used 

 for attracting fish for the sport of the angler. The juvenile representa- 

 tives of the brotherhood of the rod have generally learned to recognize 



