314 DR* T. S. COBBOLD ON HUMAN ENTOZOA. [NoV. 2.5, 



T. tenella,, Pallas, Retzius. 



T. grisea, Pallas, Schrank. 



T. membrunacea, Pallas, Batsch. 



1\ humana inermis, Brera. 



T. (a anneaux courts). Bonnet. 



T. (sans epine), Andry. 



For our knowledge of the anatomy of this species we are mainly 

 indebted to the researches of Eschricht ; and it is only very recently 

 that we have become acquainted with any part of the history of its 

 development, through the investigations of Dr. J. Knoch, of Peters- 

 burg ('Petersburger medicinische Zeitschrift,' 1861, No. 3). Some 

 account of these interesting discoveries has already appeared in a 

 review in the first volume of the 'Lancet' for the current year 

 (p. 101) ; and from these researches it would appear that the well- 

 known ciHated infusorial condition of the embryo undergoes its 

 transformations whilst still living in open waters ; from this medium 

 it is subsequently transferred to the human body, in a passive man- 

 ner, by the same waters being used as drink. A full account of the 

 larval metamorphoses is still needed ; and we are promised this desi- 

 deratum in the 'Memoirs' of the Petersburg Academy*. In the 

 mean time, it may be remarked that two distinct species of Bothryo- 

 cephalus have been described as occurring in the human body. One 

 described by Mayer, of Geneva, is extremely doubtful ; but we are 

 indebted to Leuckart for explaining the grounds on which a good 

 second species {B. cordatus) may be ranked with the already ex- 

 tended list of human entozoa. In the porpoise, I have discovered a 

 closely allied cestoid (DipJiyllobothrium stemmacephalum) ; but the 

 form of the head left me in no doubt as to its specific and generic 

 differentiation. 



30. BoTHRYOCEPHALUs CORDATUS, Leuckart. 



B. cordatus, Leuckart. 



This species is new to science, and has only very recently been 

 described by Leuckart, who received about twenty specimens from 

 the eminent naturalist, Prof. Steenstrup, These examples were ob- 

 tained at Godhaven, North Greenland, and were transmitted to 

 Steenstrup by the Danish Inspector, Counsellor Olrik. Only one of 

 the worms (about a foot long, or 26 centimetres), came from the 

 human body, all the others being from dogs, in which animal it 

 exists in considerable numbers. It differs from B. latus chiefly in 

 the form of the head, which is heart-shaped (or, rather, obcordate), 

 short and broad, and set on to the body without the intervention of 

 a long neck. The segments are distinct from the very commence- 



* This magnificent contribution to entozoology has just come to hand (Jan. 

 1863) ; but we have only space to remark that Dr. Knoch finds (contrary to 

 Kiichenmeister's statements) six hooks present in the ciliated embryos, as obtains 

 in the non-ciliated proscoleces of Tmniae. With these embryos he performed a 

 variety of interesting experiments on various animals, and succeeded in rearing, 

 in dogs, not only larval tapeworms, but also sexually mature examples of Bothryo- 

 cephalus latus. — T. S. C. 



