494 PENTASTOMIDA CHAP. 
calcareous degeneration, and Virchow states “dass beim Menschen 
das Pentastomum am hiufigsten von allen Entozoen zu Verwechse- 
lungen mit echten Tuberkeln Veranlassungen giebt.” The larva 
moults several times, 
and loses its limbs, 
which seem to have 
no connexion with 
the paired hooks in 
the adult (Fig. 256). 
The internal organs 
slowly assume the 
form they possess m 
the adult. The larva 
is at first quite 
smooth, but as it 
grows the annula- 
tions make their ap- 
pearance, arising in 
the middle and 
spreading forward 
and backward (Fig. 
259). In this en- 
Fic. 260.—Larva of Porocephalus proboscideus, seen from cysted condition the 
below, Highly maguifed (From Stles) 1, Borg; Jarva, remains coiled 
seen between the forks of the second pair; 3, ventral up for some months, 
peas ge are alimentary canal; 5, mouth; ACean dingto Leuckart; 
six in the case of J. 
taentoides, and a somewhat shorter period, according to Stiles,! 
in the case of P. proboscideus. 
The frequency of what used to be called Pentastoma denti- 
culatum (=the larval form of LZ. taenioides) in the body of man 
depends on the famiharity of man with dogs. Klebs and Zaeslin 
found one larva in 900 and two in 1914 autopsies. Laenger” 
found the larva fifteen times in about 400 dissections, once in the 
mesentery, seven times in the liver, and seven times in the wall 
of the intestine. After remaining encysted for some time it may 
07 6C0, 
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1 Zeitschr. wiss. Zool. lii., 1891, p. 85. This contains a very full bibliography, 
of 143 entries. 
2 Centrbl. Bakter. xl., 1906, p. 368; v. also Thiroux, C. R. Soc. Biol. lix., 1905, 
p. 78. 
