770 SCIENTIFIC RECORD FOR 1885. 



Nematelminths. 



Nervous system of tape-worms.-^Although the nervous system of the 

 tape- worm was discovered half a century ago, the subje ;t has remained 

 in considerable obscurity, and recent research by Dr. J. Niemiec is 

 therefore timely as throwing light on some of the controverted and 

 doubtful points at issue. Dr. Kiemiec's researches were based on sec- 

 tions of the scolices of T. coenurus, T. elliptica, T. serrata, and T. me- 

 diocanellata. The different parts are considered under four categories. 



(1) A ^^ nerve ring'''' situated under the hooks, from which " filaments 

 run to the hook musculature, while from ganglionic swellings eight 

 branches descend, four going to the principal lateral ganglia, and four 

 jirolonging their course even within the proglottides." 



(2) A " central fjanglion^^ in the middle of the " principal commissure," 

 joining the two lateral ganglia, and "from which a 'transverse commis- 

 sure' passes at right angles to the ' principal.'" 



(3) " Polygonal commissures,''^ in the plane of the two chief commis- 

 sures, formed by " nerves which unite the two latei al ganglia with the 

 branches descending from the nerve-ring and with the transverse com- 

 missure," and parallel to it, " a little below, there lies an 'inferior polyg- 

 onal commissure' of the same nature. Where the different branches 

 join, 'secondary ganglia' are situated, and from these, as well as from 

 the principal lateral ganglia, the suckers are supplied with nerves, four 

 to each." 



(4) " Spongy cords,''"' ten in number, three pairs starting from the prin- 

 cipal lateral ganglia and the remaining four (as already noted) "de- 

 scending from the nerve-ring and passing through the ' secondary gan- 

 glia.'" 



In conclusion Dr. Niemiec insists upon (1) the resemblance between 

 the nervous system of the tape-worms and that of the Tetrarhynchi ; 

 and (2) the homologies of the nerve-ring of the tape-worms with the 

 oesoijhageal ring of the annelids, " from which it differs only in its less 

 pronounced development or reversion to a more rudimentary form," 

 and (3) the diminished gap which intervenes between the cestode and 

 trematode nervous systems. {Recueil Zool. Suisse, v. 2, pp. 589-648 ; J. 

 B. 31. S. (2), V. G, pp. 75, 76.) 



Annelids. 



Deep sea Annelids. — The deep-sea types of a few classes, such as the 

 fishes and Holothurians, are, to a large extent, much differentiated from 

 the shallow-water forms, but those of other classes are comparatively 

 little divergent from littoral species. Among the groups of the latter cat- 

 egory are the Annelids. The rich material collected by the Challenger 

 expedition has been the object of study to Prof. William C. Mcintosh 

 for seven years, and the results thereof have now appeared in the form 

 of a large quarto volume constituting the entire twelfth of the Chal- 

 lenger reports. 



