92 LECTURE V. 



muscular investment.* The mouth is a minute pore, situated on the 

 extremity of the uncinated proboscis : it leads to two long cylindrical 

 canals excavated in the soft parenchyme adherent to the muscular 

 tunic, and are continued to the posterior extremity of the body, send- 

 ing off throughout their course a number of fine transverse vessels 

 which anastomose together. Two short, slender, cylindrical, or flat- 

 tened bodies, are continued backwards from the sheath of the pro- 

 boscis, and are freely suspended in the anterior part of the general 

 cavity : they are called lemnisci. These bodies contain a fine gra- 

 nular parenchyme, and are richly supplied by a reticulate system of 

 vessels, which communicate with those of the lateral canals, where 

 the pedicles of the lemnisci are attached to the sheath, of the proboscis. 

 This apparatus, which in its form resembles a vascular systemj, is the 

 only part of the organisation that appears to relate to the nutrition of 

 the worm. Hunter has left some remarkable instances of the boring 

 powers of the Echinorhynchi : in No. 289, he shows the Echino- 

 rhynchus porrigens, attached to a portion of the intestine of the Piked 

 Whale {Balcena Boops, Linn.). The worm has perforated the intes- 

 tine, and has formed in its parietes a tortuous passage ; the head 

 having penetrated the mucous and muscular coats, and returned again 

 through the latter, into the intervening cellular coat. The sides of 

 the canal are composed of thickened and condensed cellular mem- 

 brane, and in the enlarged cavity which contains the head there is a 

 quantity of curdled matter, which appears to be lymph thrown out in 

 consequence of the irritation. The main body of the parasite con- 

 tinued to float in the chyle and mucus of the intestine, which may 

 be received into the fine vascular network of the skin by cutaneous 

 absorption : the uncinated proboscis serving chiefly as an anchor or 

 hold-fast. Hunter has placed this preparation in his series of " Parts 

 analogous to Teeth in Invertebrate Animals." 



The male organs consist of two fusiform testes, attached to each 

 other and to the proboscis by a suspensory band ; two varicose vasa 

 deferentia, which unite together to terminate in a single vesicula 

 seminalis ; and a long intromittent organ provided with a bursa occu- 

 pying the posterior extremity of the body, and having a special mus- 

 cular apparatus for the retraction and extrusion of the contained 

 organ. Beneath the testes there are from one {Ech. claviceps) to six 

 pyriform bodies which secrete a minutely granular matter, and whose 

 ducts, in the latter member, which is most common, unite into two 

 tubes that terminate in the bursa penis. The secretion of the proper 

 the size of the female. The generative organs in this sex consist of 

 two ovaries and one oviduct. The ovaries are long and wide cylin- 



* XXrV. p. 125. 



•f LXXVII. tab. 2. f. 10., tab. 3. figs. 10. 12. 21. LXXIX. figs. 1. 8. 



