PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 81 
Vol. VI, No. 6. Washington, D.C. June 23, 1883. 
It will thus be seen that in the supposed male, the length of the skull 
is less than twice the breadth at the zygomatic arch [653 < 698 (2 x 
349)], while in the female the length is almost exactly two times the 
breadth (654 about = 656) (2 x 528), and this holds good, not only in 
the average measurements, but in every single instance: 
8 676 < 706 (2 x 353) =| = 2655 about = 660 (2 x 330) 
$ 654 < 706 (2 x 353) | ? 645 about = 648 (2 x 324) 
$ 636 < 684 (2 x 342) | 2662 = 662 (2 x 331) 
$ 672 < 720 (2 x 360) 
3 625 < 676 (2 x 338) 
We can also express the difference by comparing the length with 
another dimension, thus: In the male the total length is less than 10 
times the breadth of the intermaxilla at the anterior angle of the nasal 
aperture [653 <710 (10 x 71)], while in the female the length is more 
than even 11 times the same breadth [654 > 638 (11 x 58)], the result 
being the same in each individual. 
6676 < 740 (10 x74) | 26555649 (11 x 59) 
$654<740(10x 74) | 2 6455,627 (11 x 57) 
$636 <720(10 x 72) | 96625627 (11 x 57) 
8 672 < 690 (10 x 69) 
$625 < 650(10 x 65) 
I think that this will be sufficient at present to show that there exists 
a well-marked difference, which can be formulated as above. Besides, 
there are numerous points in which the two groups of skulls can be dis- 
tinguished, but which cannot be expressed in figures. Unfortunately I 
cannot give minute comparative descriptions, as the skulls are already 
packed and shipped. 
The same is the case with the lower jaws, of which I herewith give a 
table of dimensions. 
Table of dimensions of mandibles of RYTINA GIGAS (Zimni.). 
Collectors’ No. o ) 
- =I 
1g ir r Ts a a 5 5 
Saree li sae) sche oliehgisnn) ail iS) espe 
bs ‘ A A A | A a | qi - | A A | a | Z ai oat = ~ 5 + 
Dimensions. SslS3u| Sal] S| Ss | 8%] 5a | 8a / 88/3, | oS] of 
birt | ber | eee | Gee | teed |) oS | NT | ON | ee | EO | tom | BF 
o- on on | 22. | oe oS on on oD 4 e e 
zhao (= b= ml = SRN gre RS Naar an VFS Ls i A 
Fe RS PE a ar ea WU 
7) Nn TU Ean 7 I) n mn iam iG <q <q 
z (aes oS Se a2 Sa ed | eS, 
] | | 
Supposed sex.-.....----. roi Sis Mie Oe beet fo) Fo ten cobs ee ens Oe eed ube a 
mm. mm. mm.) mm. | mm mm. | mm. | num. | mm.| mm.| mm.| mm. 
1. Greatest length of the 
horizontal ramus. -. 433 406 | 426 461 431 423 433 28 | 436) 451 431 434 
2. Distance from surface 
of condyles to infer- | | | 
ior, posteriorangle..| 27] 261 | 267 | 261 | 240| 297] 290] 280| 280] 297| 260 289 
Proc. Nat. Mus. 83———6 Juiy 21, i883. 
