14 HISTORY OF THE SUBJECT. 



trated edition of the ' Regne Animal/ 1 by the disciples of the great master, M. de Quatrefages gives 

 exactly the same description, and repeats certain of the figures — to be alluded to hereafter. 



Schweigger, in his ' Handbuch der Naturgeschichte, 5 follows Cuvier too closely, for he now 

 describes Borlasia anglice as having a membranous disc posteriorly, and either occurring in a free 

 state, or by aid of this disc adhering to Anomise. 3 



Dr. Fleming, 3 in 1822, represents the Nemerteans by Linens, one of the genera of his 

 family Gordiusidse, the other genus being Gordius. He correctly observes that in Linens the 

 mouth is a longitudinal slit placed under .the snout, but makes no further remark than that 

 several species inhabit this country. 



A very considerable increase to the knowledge of these animals was made by the investi- 

 gations of the celebrated Italian naturalist Stefano Delle Chiaje, who, in the second volume of 

 his 'Memorie,' 4 published in 1825, gave somewhat detailed descriptions of two Nemerteans 

 for which he constituted the genus Folia, named after the comparative anatomist Giuseppe S. 

 Poli. In his sketch of the anatomy of Folia sip/iunculus, he mentions two muscular coats 

 under the skin, an inner of longitudinal fibres, and an outer of transverse (circular). From 

 the mouth springs a muscular rugose gullet (speiserohre of the Germans), having an inner 

 mucous coat and a fibrous layer. The alimentary canal has the same diameter, and extends 

 throughout the entire length of the animal. In each articulation we have a right and a left 

 sac or pouch in connection with the alimentary tube, into which the food may enter. Above 

 the digestive tract is found a canal containing a long proboscis, which has four fibrous coats, 

 and an internal mucous one covered with papillae. The proboscis, moreover, is fixed to the 

 wall of its sac by a muscular band. He imagines this to be an organ of touch, and states that 

 when free its motions are so vermiform that one might easily mistake it for a Lumbricus or 

 Echinorhynchus. In regard to the circulation, he observes that two arteries arise from the 

 triangular lobe of the head, and proceed along the sides of the body, while two sacs, which 

 have the function of hearts, occur at their commencement. In the angle of the basis 

 are three slight whitish elevations, in connection with a whitish thread, which runs down to 

 the middle of each artery. From the end of the mouth springs a very small vein, which 

 gives branches to the lateral sacs (of the digestive cavity). In his other species {Folia lineata) 

 he describes a prehensile disc around the anus, and the occurrence of pores on the ventral 

 surface, analogous to the respiratory sacs of Sipunculus, but the position of the form is doubtful. 

 This author therefore has the merit of being the first to anatomise these animals in a scientific 

 manner, and to interpret fairly the physiology of the parts. He recognised the true mouth of 

 his examples (which belonged to the Anopla), the general arrangement of the digestive tract, 

 and the presence of distinct muscular layers in the body-wall. The errors he fell into with 

 regard to the circulatory system may be easily explained, since he worked only with dead 

 animals, or, at least, not with those capable of being employed as transparent living objects. 

 The anal " sucker" in P. lineata may have been due to some eversion of the digestive canal, if the 

 species pertained to this order. 



1 ' Regne Animal Illust/ Zoophytes, texte et atlas, p. 65, plates 33 and 34. Paris. 

 3 ( Handbuch der Naturgeschichte der skelettlosen umgegliederten Thiere/ Von Dr. August 

 Friedrich Schweigger. Leipzig, 1820, p. 591. 



3 ' Philosophy of Zoology/ vol. ii, p. 605. 



4 S. Delle Chiaje, 'Memorie sulla storia e notomia degli animali senza vertebre del Regno di 

 Napoli/ Napoli, 1823—1829. 4 vols. (Vol. ii, p. 406.) 



