26 HISTORY OP THE SUBJECT. 



mandilla (Amphiporus lactifloreus) 9 and notices the ease with which the latter species can be kept in 

 confinement. He remarks that his captive specimens thrust out their proboscides and stylets, 

 probably for the purpose of capturing the Infusoria that swarmed in his vessels. Moreover, he 

 also saw a little Folia attack a Cyclops. I am, however, of opinion that all the interesting 

 motions he witnessed in such cases were accidental, and not due to predaceous habits. There is no 

 wonder he found no debris of food in the proboscis, since this is not at all an alimentary organ. 

 He observed their tolerance of pressure between glasses under the microscope, and the fatal result 

 of immersion in fresh water, but gave no remarks of importance in regard to the reproduction of 

 lost parts. 



In the second division of the memoir he discourses on the anatomy of the Nemerteans, and 

 it may suffice at present only to allude to his results. He was certainly one of the first to 

 anatomise the animals in a truly scientific manner, and his drawings of structure, though 

 scarcely accurate, are very beautiful. He is wrong in averring that a fibrous layer exists in 

 connection with the dermal tissues ; his muscular coats of the body-wall (external longitudinal 

 and internal circular) agree neither with the arrangement in the Enopla nor with that in the 

 Anopla ; the description of the general cavity of the body is obscure and misleading, and he 

 located the corpuscular fluid there instead of in the proboscidian sheath; he altogether went 

 astray in his interpretation of the proboscis, which he took for a digestive system (dividing it 

 into proboscis, oesophagus, and intestine), and even his anatomy of the organ (proboscis), as it 

 exists, is erroneous. He only examined the circulation in the Enopla. He confounded the 

 generative with the true digestive system, and, indeed, fell behind the early observations of 

 Duges in this respect. 



In the third part he treats of the analogies and zoological affinities of the Nemerteans, 

 which he regarded as the degraded representatives of a more elevated type. While descanting 

 on their general structure and relations, he observes that the organic apparatus presents the same 

 complication in the large Linens as in the minute Tetrastemma, but the elements (of such structure) 

 undergo a degradation in the latter ; a statement which is somewhat obscure, since the types of 

 the forms differ entirely. Eor the same reason his comparison of the integuments of Borlasia 

 anylice, Nemertes balmea, and Folia filum, is fallacious. He points out that no part of the 

 vascular system is in immediate contact with the respiratory surface, while the vessels are always 

 plunged in the liquid of the abdominal cavity, which he therefore considers as the active agent in 

 nutrition. He compares this corpuscular fluid to the chyle, for, he says, into it the products 

 of digestion are transmitted directly from the alimentary tube (proboscis) ; further, it resembles 

 the lymph, because it receives the internal products of the organism ; finally, it is like the blood, 

 because it is the direct agent in the nutrition of the eggs, and, since it bathes the muscular coats 

 of the body, it is also charged with their nourishment. With so formidable an array of functions 

 for this (proboscidian) fluid, it is no wonder he asks — whether the contents of the blood-vessels 

 merit the name of blood ? tie was not aware, however, that this fluid is enclosed within a 

 special muscular sheath, and nowhere comes in contact either with blood-vessel, body-wall, 

 or ovaries. 



With regard to systematic arrangement, M. cle Quatrefages retains the class Turbellaria of 

 Prof. Ehrenberg, exclusive of Gordius and Nais, and which he would apparently link on to the 

 Trematoda of M. Milne Edwards. He does not altogether place the Planaria?, and Distomse 

 together, but mentions that if further researches should reveal the same vascular apparatus in the 



