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IX. — On the Structure of the British Nemerteans, and some New British Annelids. 

 By W. Carmichael MTntosh, M.D., F.L.S., Murthly, Perthshire. Com- 

 municated by Professor Turner. (Plates IV- XVI.) 



(Read 20th April 1868.) 



The anatomy of the soft worms variously arranged under the Nemertean 

 Order has, even in recent times, not been carried out with that completeness 

 necessary for their thorough elucidation, a state of matters partly due to the 

 confounding of the structure of one family with another, and predicating of the 

 series what investigation has but proved in one group. Few British comparative 

 anatomists have paid much attention to these animals ; indeed, Dr George John- 

 ston,* Mr Harry GooDsm.f and Dr Thomas Williams, t are the only three who 

 have left researches of any moment on the subject. The observations of the first- 

 mentioned naturalist were made many years ago, with the aid of inferior instru- 

 ments, and, though conscientious enough, are very meagre and unsatisfactory; and 

 those of Dr Williams, while also showing the defects just noted, bear evident 

 traces of imagination. Mr H. Goodsir's interpretation of structures was, from 

 his limited observations, likewise very erroneous. On the Continent, again, the 

 investigators have been more numerous, and a long list of distinguished names 

 attest the interest which the subject has received at their hands. I do not deem 

 it necessary on the present occasion to enumerate the older writers at full length, 

 since this has already been accomplished very satisfactorily by MM. de Quatre- 

 fages§ and Keferstein, || but shall refer to such of their views under the respec- 

 tive heads as may be required for the complete elucidation of the subject. Of 

 those, however, who led the way to a more correct appreciation of the structure 

 of these animals, I may particularise MM. Duges,^[ Blanchard,** and de Quatre- 

 fages,§ in France; Ehrenberg,|| Rathke,|| Max Schultze,§§ and Kefer- 



* Mag. Zool. and Bot. vol. i. 1837; and Catalogue of Worms, 1865. 



t Annals N. Hist. xv. 1845. 



J Report Brit. Assoc. 1851. 



§ Annales des Soc. Nat. 3 me ser. vi. 184(3 ; and Voyage en Sicilie, vol. ii. par MM. Edwards, 

 de Quatrefages, and Blanchard. 



|| Zeitschrift fiir wiss. Zool. xii. 1863. 



If Annales des Sc. nat. torn. xxi. 1830. 

 ** Annales des Sc. nat. 3 me ser xii. 1849. 

 ft Symbolee Physicse, 1831. 



JJ Neueste Schrift. der Naturforsch. in Danzig, 1842. 

 §§ Beitrage zur Naturg. der Turbellarien, 1851 ; and Zeitsch. fiir wiss. Zool. iv. 1853, &c. 



VOL. XXV. PART II. 4 I 



