Miscellaneous, 79 



fourth pair tliat they possess on issuing from the e^g. When the 

 males have the fourth pair of legs disproportionately large, these legs 

 remain small throughout the preparatory state, and only acquire their 

 large size under the skin of the nympha before the last moult. The 

 larva) undergo from two to three moults before passing to the state 

 of nymphae. They have only one pair of hairs at the apex of the 

 abdomen. 



The Nymphce. — The impuberal octopod individuals, or nymphae, 

 show no distinctive sexual characters. In those species the males 

 of which have the fourth pair of legs disproportionately large, these 

 remain small during the whole of this state, and increase in size 

 under the skin before the last moult, at the same time that the 

 sexual organs are produced. At the same period are formed the 

 posterior prolongations of the abdomen in some species ; and at its 

 close the sex of the individuals may be distinguished. 



In the larva from which a nympha is to be produced, the fourth 

 pair of feet are seen beneath the skin, folded forwards. These and 

 the lobes and hairs borne by many nymphae are evidently produced 

 beneath the skin of the larva. The nymphae have two pairs of long 

 setae at the apex of the abdomen. 



The nymphae have only the single granular tegumentary plate of the 

 epistoma, the thoraco -abdominal plate of the sexual individuals being 

 wanting in them. They undergo two or three moults in this state. 



The coupled females. — These, although larger, are not always easy 

 to distinguish from the nymphae ; in some species they have two 

 colourless appendages to the hinder part of the body, which do not 

 exist in the nymphae. This copulation of adult males with indi- 

 viduals having no sexual organs is remarkable, as nothing of the 

 kind has been observed in Tyroglyphus, Glyciphagus, &g., although 

 a similar phenomenon was noticed in Psoroptes by .Bourguignon and 

 Delafond. In these avicolar Sarcoptidae a female may often be seen 

 in copulation and retained by the male, showing through her integu- 

 ments a female with well- developed genital organs. The adhesion 

 of the male to the female is effected by meains of the two anal disks 

 possessed by the former. The adhesion lasts for some days, but the 

 actual coition seems to occupy but a small portion of this time. The 

 ova are developed in the ovaries of the females whilst still in this 

 nymph- like form, and before the final moult. 



The author remarks upon the relationships of these parasitic Sar- 

 coptidae, and gives the following list, in a note, of the forms observed 

 by him, which will be fully described in his memoir: — 1. Ptero- 

 lichus, g. n., including 5 new species ; 2. Dermalkhus (Koch), sp. 

 passerinus (Linn.), oscinum (Koch), and 1 new species ; 3. Ptero- 

 nyssus, g. n., sp. Dermal, picinus (Koch) ; 4. Proctophyllodes, g. n., 

 sp. Dermal, glandarinus (Koch), and 4 new species ; 5. Pterodectes, 

 g. n., with 3 new species. — Comptes Itendus, tome Ixvi. April 20, 

 18G8, pp. 776-786. 



Th5 Pelvis and. Hind Limbs of Whales. 

 Professor Yan Bcueden has read a -paper at the Academy of 



