320 Miscellaneous. 



Troglodytes and also of the Madrepore, there was some little vitality 

 perceptible for two or three days in the least injured portions. 

 Previous to the occurrence, they were all in perfect health. 



Ilfracombe, March 19, 1859. 



Observations on the Development and earhi Condition of the Penta- 

 stoma tsenioides. By Professor Leuckart, Giessen. 



By a very interesting series of researches. Dr. Leuckart has been 

 enabled to show that tlie Pentastoma denticulatum is nothing more 

 nor less than the young condition of P. tcenioides. The manner in 

 which he proved this was as follows. Having obtained three appa- 

 rently healthy dogs, he infected their nasal passages with some dozens 

 of P. denticulatum taken from the abdominal cavity of a rabbit. On 

 killing one of the infected dogs, at the end of six weeks, he found in 

 its nose a few small specimens of Pentastoma, resembling in many 

 respects the P. tcenioides. 



The second dog was kept ahve until the end of the seventeenth 

 week ; and the result of this experiment was much more satisfactory, 

 for no less than thirty-nine specimens of the Entozoa were found in 

 it. The characters, too, of the specimens were so well marked, that 

 there remained no doubt of their being P. tcBuioidcs. Nearly one- 

 half were males (15-16 mm. long). The females were considerably 

 larger than the males (26 mm.). The animals seemed to have already 

 copulated, for the spermatheca of the females contained spermatozoa. 

 The author thinks that at the time of impregnation the oviduct is 

 but little developed, being in fact nothing more than a straight tube, 

 not longer than the penis of the male. According to him, it is after 

 copulation that the oviduct attains its enormous length. 



The third dog was killed at the end of six months, and both its 

 nose and frontal sinuses were found filled with fully-developed 

 Pentastoma tcenioides. Only two males were present, and these 

 were not larger than those examined eight weeks previously. The 

 females, on the other hand, were almost twice as long as when 

 last seen ; some of them now measured 6.5 mm. ; their oviducts 

 were fully grown, and contained eggs in the various stages of 

 development. 



The embryos of the P. tcEnioides have a similar form to those of 

 the P. proboscideum described by Van Beneden, and have also a 

 general resemblance to those of the P. multicinctum described by 

 Harley. 



Dr. Leuckart concludes from his researches that the P. denticu- 

 latum of the rabbit is the early condition of the P. tcenioides of the 

 dog, and that it takes about a year for the embryo to become trans- 

 formed into the perfect animal. — Notes from the Zeitschr. f. rat. 

 Medic, Dritte R. Bd. iv. p. 78. 



