47 



until a thin margin corresponding to the worm was left. The tail of 

 this Entozoon is represented in fig. 11. 



The third species is the smallest of the whole, and from this cir- 

 cumstance has been named Strongylus minor, neither the male not- 

 female much exceeding an inch and a quarter in length. It occurred 

 in the venous sinuses of the head and in the cavity of the tympanum, 

 and from living in blood they were of a reddish hue. The females 

 rather exceeded the males in size, and both sexes tapered gradually 

 from the head to the tail, which was much more evident in the male 

 than in the female, in which peculiarity it resembled the male of the 

 Strongylus injiexus before noticed. Nothing else remarkable was 

 observed in the male except at the tail (fig. 12), where the membra- 

 nous investment was thrown into a semicircular fold, and in it three 

 tolerably large horn-like processes, much larger than those of the con- 

 volutus (fig. 12,a), were observed : nearly at the end of the body of the 

 worm there was a dark oval mass, connected either with the genital ap- 

 paratus or with the intestine, (fig. 1 2, b) . In the female the ovarium com- 

 menced at the junction of the upper with the middle third of the body. 

 It consisted of two convoluted ducts, which ultimately united into one 

 and terminated on the side of the tail. Ova in different stages of de- 

 velopment were observed in all the females of this species, but they 

 were much smaller than in any of the others. The tail of the female 

 is represented at fig. 13. 



The fourth species was found in the lungs of the porpoise which I 

 had for dissection on the 9th of last month. On examining minutely 

 the surface of the lung, it was found that its pleuritic investment was 

 raised into little tubercles about the size of a small pea ; and on cut- 

 ting into one of these five very long and slender white worms were 

 drawn out, one being much shorter than the rest, this I subsequently 

 ascertained to be the male. On tearing a portion of the lung, a vast 

 number of these cysts were found imbedded in its substance, and in 

 each one there were several worms coiled up in a very small compass, 

 and the cysts could be readily torn away quite entire from the sur- 

 rounding tissue with the worms in them. On examining some of these 

 specimens microscopically, I found that it was a distinct species from 

 any of the preceding : it approaches nearest to the convolutus, but it 

 differs from this in many points. The males were few in number, and 

 about an inch in length, the female being three inches and sometimes 

 more. Besides this great disparity in size, both sexes were inclosed 

 in a very thin and delicate membrane, which projected from their 

 sides, and made them appear more than as wide again as they really 



