LAGENORHYNCIIUS OULIQUIDENS. 



97 



two are very ueaiiy equal iu length. The premaxillie scarcely form 

 auy i)art of the palate iu ohliquidens, but appear iu uearly the whole of 

 its distal half iu acutus. 



There aie numerous other differences of proportions in the skulls 

 which are equally striking. Taken together they form a sufiQcieut basis 

 for specific distinction. 



The numerical relations of parts in the skeletons also offer characters 

 for discrimination. The number of vertebrse in specimens of L. obliqui- 

 dois, L. acutus, and L. alhirostris, are as follows : 



Collection. 



Species. 



F. S.N.M. 

 U. S. N.M. 



K. C.S.E 



Ij. ohliquidens (n.r. adult). 

 L. ohliquidens (14:!29, Jnv.) 

 L. acutus (I^oeliiiuu) 



L alhirostris (3028) 



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

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

 skeleton of .L. ohliquidens, however, makes it necessary to allow for one 

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

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

 but seventy-nine vertebrai. The transverse iirocesses of the twenty- 

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

 truly lumbarin character and do not appear to have given attachuient to 

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

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

 teen i^airs the character will probably jDrove 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 in the left manus of our skeleton of L. 

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

 should probably be added iu the case of figures ill, IV, and V, as the 

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

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

 III, G; IV, 2 ; v, 1.* Malm, it should be observed, gives quite a differ- 

 ent formula, for L. acutus, namely, i, 2; ii, 10; iii, G(4-l); iv, 3 (+ *?); 

 V,2.t 



In ohliquidens the transverse processes of the posterior lumbar verte- 

 bra} point forward, but in acutus backward. 



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

 L. ohliquidens must be compared. These are L. thicolea and L. clanculus. 

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

 isting between the skulls of L. thicolea and L. ohliquidens. The rostrum 



*Van Beneden ami Gervais. Osteograpbio des Cetac^es, pi. XXXV, fig, 33, 

 tMalm, Hvaldjur i Sveriges Mnseer, ai" 1SG9, p. 70. 



18378— Bull. 36 -1 



