242 REPORT — 1851. 



In the recently published researches of M. Emile Blanchard * on the ana- 

 tomy of the Entozoa, physiological opinions are expressed which lend support 

 to the errors already exposed. 



This naturalist, to whom science is so much indebted, characterized the 

 voluminous spongy organ which constitutes by far the greatest part of the 

 bulk of each segment of Tcenia Solium as the true ovary, entering into mi- 

 nute details to prove the existence in each ring of an oviduct and vulva, and 

 asuperaddedsperm-producingapparatus, demonstrating thus the independence 

 of each segmental division, as regards at least the reproductive system. M. 

 Blanchard recognises in the minute, lateral, smooth-sided and wwsacculated tu- 

 bular threads, running straightly in parallelism with each border of the body, 

 what he calls the " gastric canals," communicating with each other by means 

 of commissural transverse branches. A system of true blood-vessels coin- 

 ciding in distribution with the former is also described by this anatomist. 



Now, if the views of M. Emile Blanchard be true with reference lo the 

 organization of the cestoid Entozoa, those now to be propounded in rela- 

 tion to the anatomy of the Nemertinidce must be untrue. Both cannot be 

 admitted into the category of truth ; they are irreconcileably opposed. 

 Though at variance with the fashionable doctrines of the schools, it may be 

 enounced as an absolute law, that in the ceconomy of all inferior organisms 

 the alimentary exceeds the reproductive system in size and importance. The 

 gastric and intestinal organs form in all instances a considerable part of the 

 bulk of the body. The dissections of M. Blanchard have reduced those of 

 Tcenia to dimensions of utter insignificance. His descriptions are sanctioned 

 by no analogy. It is not difficult to demonstrate that the zoological affinities 

 of the cestoid Entozoa suggest conclusions with regard to their organization 

 which the isolated and undirected results of dissections cannot disprove. 

 When however the mind of the anatomist is first awakened to a conception 

 of the typical principle of structure which prevails throughout the JVemerti- 

 nidce, Planarice, Trematoda, on the ground of their zoological consecutive- 

 ness in the scale, he will cease to doubt that the same principle of structure, 

 though opposed to his anatomical observations, obtains amongst the cestoid 

 Entozoa. It is really, however, in practical anatomy easy to establish a unity 

 of plan in the organization of this series. The direct continuity of the Ento- 

 zoan and Annelidan chains is rendered unquestionable by investigations thus 

 directed. Although the laborious researches of M. Emile Blanchard render 

 it probable that no oral orifice f exists in Tcenia, the digestive character of 



* Annales des Sciences Naturelles, 1848, 1849. 



f At the present stage of my investigations, I by no means'desire to commit myself to this 

 doctrine. On the faith of the trustworthiness of M. Blanchard as an observer, I concede for 

 the present, argumenti gratia, the probable truth of his results. But on this admission it is 

 not difficult to show that Tcenia is clearly within the boundaries of the plan of structure on 

 which the Nemertinidae (under which designation I would rank the freshwater Gordiusida, 

 the Planariada, the genera Borlasia, Lineus and Serpeniaria (Goodsir)) are organized. I 

 have hitherto enjoyed only an imperfect opportunity of dissecting tlie Tape-worm, my ob- 

 servations having been confined to a few segments from the mid-body ; but I have seen 

 enough of its structure to convince me that it falls witliin the type prevalent throughout the 

 Liniadds, Borlasia and Planaria ; that the great central organ, which hitherto all anatomists, 

 including M. Blanchard, have concurred in regarding as llie ovarian apparatus, is in truth a 

 great digestive cecum. If it be true, as affirmed by Prof. Owen, and after liim by M. Blan- 

 chard, that neither an orsd nor an anal orifice exists in Tienia, then the ahmentary fluid upon 

 which the parasite subsists must be drawn by suction through the suctorial discs, directly 

 into the interior of the digestive caecum ; aud as these suctorial discs are not perforated, but 

 covered by a porous membrane, the food is fllered a.s it is being drawn into the body. This 

 arrangement, however, by no means requires that any other than a digestive function should 

 be assigned to the spongy organ commonly known as the ovarium ; for in Borlasia, Lineus 



