244 DE. T. S. COBBOLD ON TILE PAEASITES OF ELEPHANTS. 



In 1864 I went fully into this question, and endeavoured to show that, at least as regards 

 the common fluke, the priority of the genus established hy Linnoeus was indisputable. 

 The genus Fasciola was accepted and recognized some twenty years hefore the genus 

 Distoma was proposed hy Retzius, and more than thirty years before it was adopted by 

 Zeder and his followers. (For dates, &c, see my ' Entozoa,' 1SG4, p. 149 ; also ' Para- 

 sites,' 1879, p. 15). 



As furnishing interesting evidence of the value of cooperation in zoology, I may 

 mention that in one of my earlier notices I appealed to American naturalists, requesting 

 them to examine the original specimens of Fasciola Jaclesoni preserved in the Boston 

 Museum. This appeal met with a suitable response at the hands of Dr. R. H. Fitz, who 

 afterwards published the results of his anatomical inquiry. In regard to the original 

 find, we are told that "Dr. Jackson preserved a large number of flukes, and generously 

 placed them at the disposal of Dr. H. P. Quincy, avIio made and presented to the Warren 

 Museum a series of admirable preparations." These preparations consisted of longi- 

 tudinal, transverse, aud other sections, stained in carmine, and rendered transparent in 

 the oil of colours. Dr. Fitz expressly states that a study of them satisfied him that my 

 " surmise " as to the true character of the species they represented was correct ; and I 

 am glad to perceive that so able an observer did not hesitate to accept the generic 

 nomenclature that I had adopted. 



The anatomical investigation made by Dr. Fitz resulted in not a few clear additions to 

 our knowledge, especially as regards the sexual organs. There is a very close corre- 

 spondence between the arrangements of the reproductive parts of this species and those of 

 the common fluke. In some particulars Dr.Fitz's observations and my own are at variance. 

 Thus Dr. Fitz appears to think that I have erred in attributing to Fasciola Jacksoni the 

 possession of integumentary spines. In my original diagnosis I affirmed that the body 

 is " armed with minute spines." I still adhere to that matter-of-fact statement ; but Dr. 

 Fitz says : — " Instead of finding the body armed throughout with minute spines, the 

 cuticle covering the abdominal surface presents a series of ridges pointing backwards, 

 and extending the entire length of the animal. Traces of a similar formation are present 

 on the dorsal surface or the neck ; elseiohere the back is smooth." The italics are mine. 

 I am sorry to correct Dr. Fitz. The little spines not only 

 exist, but when the skin of the parasite is examined by direct s " 



light under a 2-inch objective, their equidistant and otherwise 

 regular arrangement becomes obvious. Under higher powers 

 the spines are measurable, giving an average of y^j to -jirs °f 

 an inch in length, their basal diameter being less than -^hro 

 of an inch. It must be admitted that their size is insignificant 

 when compared with the similar dermal spines of the common 



n , TT ,. 77 , . , i . -i • i Eight cutaneous spines of 



nuke. In Fasciola hepatica the spines are about twice as long D Fasciola Jacksoni 



and thrice as broad. The differences therefore are sufficiently ( x 2 ^0 diam.). 



striking to be emphasized in any diagnosis of the species ; 



and, further, it may be said that they are perfectly independent of the ridges or folds of 



the skin described by Dr. Fitz. 



