the Origin of Intestinal Jforms, S5i 



account and drawing of those from the Loligo, calling them 

 seminal vessels. Those from the Mediterranean Octopus^ 

 were slightly described by Cuvier as '* les fameux filamens, 

 machines ou animalcules decouverts par Needham," and are 

 apparently the species minutely described by Carus as Need^ 

 hamia expulsoria. Those from the Sepia officinalis are repre- 

 sented by Professor Rudolph Wagner of Erlangen as bemg 

 very like Echinorhynchi^ which implies a very different form. 

 In an Octopus from St Thomas's, I lately found in the same 

 sac adhering to the testis, a number of Needhamiae, forming a 

 new species. 



Sect. 5. The Spermatozoa are not Parasitic Animals. — These 

 curious bodies being regarded parasitical, a very different opinion 

 must be formed respecting the Spermatozoa. The modern in- 

 quiries by Rud. Wagner, Valentin, Henle, Siebold, (Sec, which 

 may all be found in Rud. Wagner's recent Manual of Physiology 

 (of which the first volume appeared in 1839), have furnished 

 science with several very important new facts, the most 

 striking of which is the gradual and regular development of 

 the Spermatozoa in small sacs. Being thus proved to be es- 

 sential parts of the seminal fluid, they must be considered 

 as analogous to the globules of the blood. Their apparently 

 voluntary motion by no means warrants the inference that 

 they are distinct animals. The continuance of motion in mi- 

 croscopical parts of the body, after they have been separated 

 from it, may be seen in the cilise upon the epithelial cells of 

 certain mucous membranes, forming the famous vibratory mo- 

 tions of Dr Sharpey, Purkinje, and Valentin. This analogy 

 may be regarded the stronger, as no internal organs are found 

 in the Spermatozoa ; and we are not aware of any fact in- 

 dicating their power of propagating their own species. In 

 the Nematoidean worms, I have observed a certain condition 

 of the analogous parts, which perhaps may throw new light 

 upon their mysterious functions. The testis of the Ascaris 

 lumhricoides is well known to have the same cylindrical form 

 as the horns of the female organs. The structure of the in- 

 terior also seems to be analogous. I believe I have observed 

 a central cord analogous to the rachis {vide supra) of the 



