LAGENORHYNCHUS OBLlCiUIDENS. 



97 



two iue very iie;iily equal in leugtli. The pre-inaxilla' scarcely form 

 any part of the pahite iu ohliquidens^ but appear iu nearly the whole of 

 its distal half in aentiis. 



There aie numerous other differences of proportions lu the skulls 

 which are equally strikiug. Taken together they form a sufficient basis 

 for specific distinction. 



The numerical relations of parts in the skeletons also offer characters 

 for discrimination. The number of vertebric in specimens of iy. ohliqui- 

 deris, L. aoutHs, and L. albirostrls, are as follows : 



Collection. 



U. S.N.M. 



U.S.N.M. 



11. C. S. E 



Species. 



L. (•hliquidens (n.r. ailiilt). 

 L. ohliquidcns (14I!29, Jiiv.) 

 L. acutun (I'oeluiiiu) 



L alhirostris (3028) 



The last-named species clearly has many morcTertebrre than L. acutus, 

 while L. obliquidcns has fewer. A critical examination of the immature 

 skeleton of i. obliquidens, however, makes it necessary to allow for one 

 or possibly two more caudal vertebrie, so that the total number in the 

 latter species is brought nearer that in L. acutus, which sometimes has 

 but seventy-nine vertebrae. The transverse processes of the twenty- 

 first vertebra in the immature skeleton of L. ohiiquidens are long and 

 truly lumbar in character and do not appear to have given attachment to 

 a fourteenth pair of ribs, but such a pair would doubtless be fouud in 

 some specimens of a series, and as L, acutus sometimes has but four- 

 teen pairs the character will probably prove of no value in distinguish- 

 ing the species. The difference in the relative number of lumbar and 

 caudal vertebrae can not be in like manner disposed of, and would ap- 

 pear to constitute a real distinction between the two species. 



The number of phalanges iu the left manus of our skeleton of L. 

 obUquidens is as follows: i, 2; II, 7; ill, 5; iv, 1;V, 0. One phalange 

 should probably be added in the case of figures ill, iv, and v, as the 

 specimen appears to be defective at these points. The numbers would 

 then agree with those given by Gervais for L. acutus, viz. i, 2; ll, 7; 

 III, C; IV, 2 ; V, ].* Malm, it should be observed, gives quite a differ- 

 ent formula, for L. acutus, namely-, i, 2; ii, 10; iii, G( + l); iv, 3 (+ ?); 

 V, 2.t 



In obUquidens the transverse processes of the posterior lumbar verte- 

 brjie point forward, but in acutus backward. 



There are two other species (known only from the skulls) with which 

 L. obUquidens must be compared. These are L. thicoka and L. clanculus. 

 The measurements given on p. 100 sufficiently indicate the differences ex- 

 isting between the skulls of L. thicoJea and L. obUquidens. The rostrum 



*Van Benedeu atid Gervais. Osteographie cles Cetac6es, ])!. XXXV, fig, .33. 

 tMalni, Hvnldjiir i Svcriges Mnscer, ar 18G9, p. 70, 



18378— Bull. 30 7 



