1879.] MR. W. A. FORBES ON THE GENUS LATHAMUS. 173 



made ; and till that is done it is perhaps somewhat premature to 

 generalize. Nevertheless, having examined somewhat carefully a con- 

 siderable number of the skeletons of the two groups with which 

 Lathamus has been generally associated, I have, I believe, been able 

 to detect certain differences which will help us in referring the bird 

 at present under discussion to its proper place. 



First, as regards the skull. This, in all the Trichoglossince, is 

 remarkable for its somewhat depressed form and the lateral compres- 

 sion and elongation of the upper and lower jaws, the mandible when 

 deprived of its horny sheath showing even more clearly the peculiar 

 shape of the lower jaw in these birds, first pointed out by Suudevall 

 and already alluded to above (PI. XVI. fig. 7). In the Platt/ctrci 

 the skull is less depressed above and much shorter in proportion, and 

 the mandible is not pointed, but has its symphysial portion wide, 

 deep from above downwards and somewhat truncated. The same 

 is the case in Lathamus (PI. XVI. fig. 8). 



In the Lories the lengthening of the beak has led to a similar 

 elongation in the anterior limb of the palatine bones, so that this part 

 is as long as, or longer than, the posterior one ; and the latter is con- 

 siderably shorter than the pterygoids. In the Platycerci the an- 

 terior part of the palatines is not so elongated ; but, on the contrary, 

 the posterior limb is somewhat lengthened, and, in fact, nearly as 

 long as the pterygoids. Here, again, Lathamus agrees more with 

 the Platycerci. 



In the Lories (PI. XVI. fig. 9, Eos rubra) the anteorbital pro- 

 cesses are much larger and better-developed than in the Platycerci, 

 where the hinder margin of these parts, as seen from above, is not 

 very far from being on a level with the cranio-rostral suture, and so 

 causes the orbits to take up a larger part of the surface of the skull 

 (in a view from above) than in the other group. The same is the 

 case in Lathamus^ (PI. XVI. fig. 10). 



The retention of the furcula is no doubt associated with the rapidity 

 of flight of this bird, whilst in the more slowly moving Platycerci it 

 has disappeared almost entirely. As we already know from M. 

 Blanchard's researches (Ann. Sci. Nat. Zool. xi. pp. 84-85, 1859),. 

 but little assistance as regards classification can be gained in this 

 group from a study of the sternum. 



The pelvis, however, has been of more use to me. 



In the Lories this is always elongated and narrow in proportion, 

 the preacetabular part being particularly elongated, and the iliac 

 foss« on each side for the attachment of the gluteal muscles being 

 deeper and more extensive. In the Platycerci and Lathamus the 



> Bonaparte (Compt. Eend. xliv. p. 536, 1857), following Owen (Cat. Osteol. 

 Series E. C. S. 1853, p. 279, no. 1451), says that in Lathamus the orbit is com- 

 pleted below by the junction of the lacrymal with the " mastoid." This is 

 certainly not the case in a skull lent to me by Professor Garrod, and, if true, 

 would be an anomaly for any member of either of the above-mentioned groups. 

 In the specimen referred to in the Museum of the College of Surgeons (no. 1451) 

 it appeared to me on examination that there was in reality no bony union be- 

 tween the two bones, which were connected simply by ligament. 



