1888.] ON THE STERNAL GLAND OF DIDELPHYS DIMIDIATA. 353 



with Heterodactylus, affords a striking confirmation of the correct- 

 ness of these conclusions. As may be seen from the drawing 

 (fig. A, p. 3o2), the scaling of the reproduced tail of Gymnoph- 

 thalmus is that of a Heterodactylus or Cercosaurine Teioid. 



Another example (see fig. B, p. 352) is afforded by the tail of 

 Opkisaurus {Pseudopus), a genus which I have, following Cope, placed 

 in the same family as the Slow-worm {Anguis). Here we have a 

 Lizard with verticillate scales, the tail of which, when reproduced, 

 assumes the cycloid scaling of its Diploglossine and, no doubt 

 ancestral, allies. 



According to the taxonomic arrangement of all the older and of 

 many modern authors, such tails as are represented in the above 

 figures exhibit, on the same individual, a ' chasse-croise' of the 

 characters of two primary divisions, viz. the " Cyclosaura" (normal 

 tail of Ophisaurus and reproduced tail of Gymnophthalmus) and the 

 " Geissosaura " (normal tail of Gymnophthalmus and reproduced 

 tail of Ophisaurus). 



It will be useful in future to pay greater attention to the scaling 

 of the renewed tails of Lizards, as it may, in some cases, afford a 

 clue to the affinities of genera or species to one another. 



4. Note on the Sternal Gland of Diclelphys dimidiata. 

 By Frank E. Beddard, M.A.j Prosector to the Society. 



[Received June 5, 1888.] 



At a recent meeting of this Society (see P. Z. S. 1887, p. 527) 

 I described the external appearance and the minute structure of a 

 peculiar gland va. Myrmecobius, situated just above the anterior end of 

 the sternum. 



I have now to record the presence of a gland occupying a similar 

 position in another Marsupial, viz. Didelphys dimidiata (Wagner). 

 Mr. Thomas has directed my attention to the presence of this gland 

 and requested me to report upon its minute structure. 



One of the drawings which I now exhibit (fig. 1, p. 354) 

 represents the head and anterior region of Didelphys dimidiata and 

 shows the position of the sternal gland. 



The second drawing (fig. 2) represents the gland magnified more 

 highly. 



The integument in this region appears to the naked eye to be 

 entirely devoid of hairs, and the skin is furrowed in various directions. 

 The latter figure may be compared with fig. 2 of my paper upon tlie 

 sternal gland of Myrmecobius (P. Z. S. 1887, p. 528). The orifices 

 of the glands upon the exterior are by no means so plain as in Myrme- 

 cobius. It is of course possible that the appearance of the glandular 

 patch in Didelphys owes its difference from the appearance of the 

 corresponding structure in Didelphys to the state of contraction of 

 the skin — caused by the alcohol in which the animal was preserved. 



In Myrmecobius the glandular patch upon the integument had a 



