Microscopical Society of London. 1041 



both above and below the uterus, a distension then takes place between these constric- 

 tions, and a surrounding membranous structure is thrown off, which becomes of a 

 milky white colour; into this the animal forces with some effort the whole contents of 

 the uterus. This done, it elongates the anterior portion of the body, and withdraws 

 its head as from a collar. After the animal has firmly fixed it to some substance, it 

 fashions it with its mouth until it presents an oval form. This description enables us 

 in some measure to account for the mammaeform appendages of the homy case of the 

 species under consideration, and which differs somewhat in the structure of these parts 

 from all the cocoons described by Dr. Johnson, in which, instead of the protuberant 

 mammae, we find simply circular orifices ; but it does not in any shape enlighten us 

 upon the mode of the construction of the extraordinary and complex spongeous tissue 

 which surrounds our species of cocoon. The mammaeform ends of the cocoon are of 

 an oval form, and project in about an equal degree beyond the inner and outer surfa- 

 ces previously to their becoming perforated, and the length of the oval is somewhat 

 increased by a considerable thickening of the substance of the body immediately sur- 

 rounding them. The communication between the inner and outer surfaces appears to 

 be effected in a very singular manner. In one case where I made a section of one of 

 these organs at right angles to the natural surfaces of the body, it appeared perfectly 

 solid ; in another a small cavity only existed near the inner surface of the case ; but 

 in a third specimen the appearance presented was of an exceedingly singular descrip- 

 tion. The outer end of this organ had a small irregular perforation which led into an 

 ovoid cavity immediately beneath, and the long axis of which was in a diagonal direc- 

 tion as regards the axis of the body of the cocoon, and the inner surface of this cavity 

 appeared to be furnished with three or four ribs. Upon opening the cocoon I found 

 that the opposite end of the mamma had disappeared, and in lieu of solid substance 

 there was a large dome-shaped cavity, the top of which was separated from the inner 

 end of the ovoid cavity in the external end by a very thin layer of horny structure : 

 and indeed at one spot there were appearances as if a minute communication existed 

 between them, but from the oblique position of the ovoid cavity I could not determine 

 this with certainty. The other extremity of the cocoon did not exhibit precisely the 

 same appearances ; in this case the entrance to the ovoid cavity was much larger on 

 the outer surface, while on the inner one the entrance to the large cavity was closed by 

 an apparently stout membrane." — p. 302. 



Microscopical Society of London, June 18, 1845. — Thos. Bell, Esq., F.R.S., Pre- 

 sident, in the chair. Read, a paper by George Shadbolt, jun., Esq., ' On a British 

 Species of Ixodes found upon Cattle.' The insects forming the subject of the present 

 paper, were found on some cows belonging to a farmer residing at Chingford, Essex, 

 on the borders of Epping-forest. They are known to the country people by the name 

 of the * tick,' but they are aware that they differ from the insects of that name which 

 infest sheep and goats. They are found upon cattle, attacking all parts indiscrimi- 

 nately, and causing much irritation and annoyance to them. They have been found 

 to the number of several hundreds on a single cow, and have also been known to at- 

 tack even human subjects, though this is not common : and although it is probable 

 that they infest other animals, the author has seen them only on cows. They do not 

 appear to breed on the animals infested, but are produced in the forest into which the 



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