314 DR. T. S. COBBOLD ON HUMAN ENTOZOA. [Nov. 25, 
T. tenella, Pallas, Retzius. 
T. grisea, Pallas, Schrank. 
7’. membranacea, Pallas, Batsch. 
T. humana inermis, Brera. 
T. (& anneaux courts), Bonnet. 
T. (sans épine), 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 ciliated 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 (Diphyllobothrium stemmacephalum) ; but the 
form of the head left me in no doubt as to its specific and generic 
differentiation. 
30. BorHryOCEPHALUS 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 
along 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 Tenie. 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. 
