PENTASTOMA T^NIOIDES. 397 



m detail. So far as my own observation extends, the pupa, in its 

 later stages, closely resembles tlie free larva, but, as Leuckart's 

 researclies show, the earher stages are very dijSerent. The embryo, 

 after encystation, repeatedly casts its skin, and during the intervals 

 of these several successive moultings, the young animal makes 

 rapid growth, accompanied by a series of striking structural 

 changes. Passing through these it, at length, acquires the perfected 

 larval state, or that known as the Pentastoma denticulatum. This 

 stage has been described by numerous observers, but, in order to 

 save space, I shall content myself with reproducing the facts 

 which I have myself observed and recorded elsewhere.* 



On the 10th of February, 1 859, I obtained numerous examples 

 from the viscera of a Bubale {Antilope bubalis, Pallas), which had 

 died the day previous at the Zoological Society's Gardens. The 

 greater part of these worms occupied the surface of the lungs and 

 intestines ; a considerable number, however, being enclosed in 

 cysts beneath the pulmonary pleura. Fifteen or more having 

 been taken away for the purposes of microscopic examination and 

 experiment, I had ample opportunity of watching the movements 

 of the cephahc claws whilst the animals were still living. I may 

 here remark, that these claws do not in any way resemble those 

 of the tapeworm family, but, in strict accordance with other 

 external features, show that the Pentastomes belong to an entirely 

 different type. Placed under the half-inch objective, with the 

 ventral surface uppermost, the transparency of the body permits a 

 fuU view of the apparatus of hooks, as displayed in the accompany- 

 ing drawing (PI. XXI., Fig. 3). It will be noticed that the points of 

 the claws are directed towards the observer, and not towards 

 the longitudinal axis of the body, as Kiichenmeister's figurtj 

 (" Parasiten," Table YIII., fig. 11) would lead one to suppose; more- 

 over, the claws are placed obliquely in reference to the central line, 

 the angle of divergence being about 26°. During the eversion and 



* " Linnean Society's Transactions," Vol. xxiii., p. 350. 



