Notices of Irish Entozoa. 519 



is entirely owing to a forcible distention of the worm from 

 imbibed water. I have never known nor heard of any instance 

 of an Entozoon being seen in this state in its natural habitat, 

 and I believe that it will invariably be found that where the 

 disruption has occurred, the animal had been previously ex- 

 posed to the influence of fresh water. Moreover, in some 

 Cucullani which I lately obtained from the intestines of a ve- 

 ry large conger eel, (but the species I have not yet determi- 

 ned), the distention from fresh water, and a, return to the flac- 

 cid state in the salt solution took place exactly as in the 

 Echinorynchi ; and of two specimens which burst in a short 

 time, in distilled water, one was a male, (as was evident from 

 the exserted penis), and in it the spermatic tubes were explo- 

 ded from the rupture, along with a portion of the intestine, 

 the latter in form of a loop, owing to the continuity being un- 

 broken. In a future paper I will have to recur to this sub- 

 ject in referring to a very beautiful and singular phenomenon 

 connected with the protrusion of the ovaries in the Cuculla- 

 nus PlatisscB. 



To return to our more immediate subject. The female 

 Echinorynchus Acus is above two inches in length, and is 

 said to attain the length even of three inches, but this I have 

 not observed. The male is generally about half an inch long 

 but sometimes nearly an inch. The colour is very various, 

 but generally white when distended, though frequently ac- 

 companied at the same time by a tinge of orange, pink, or 

 cinereous. Sometimes the whole animal is reddish orange, 

 (especially the male), and sometimes the whole is ivory white, 

 with a solitary minute crimson dot here and there. Two ob- 

 long longitudinal orange spots, more or less vivid, are placed 

 immediately behind the root of the proboscis ; these however 

 are sometimes very faint, and sometimes have the appearance 

 of a single mark. In the undistended state the colour of the 

 worm is not unfrequently a dirty umber, and so disposed as 

 to give an annulated appearance to the specimen ; but, in 

 short, the colour is extremely variable, though whether as 

 Fabricius conceived this is dependent on that of the contents 

 of the intestine, I am not fully satisfied. It is certain that 

 in a mass of individuals found in the same portion of intes- 

 tine, considerable diversity of colour prevails, and where 

 there has been only a transparent mucus present, I have found 

 specimens of a pure white, and others of a bright orange. 



The sexes differ much from each other in thickness as well 

 as length, the male being of nearly the same diameter through- 

 out, while the female is anteriorly much thicker than else- 

 where. 



