(j THOMAS DWIGHT ON THE 



a decussation and tlit' series from the inner side to the head is more distinct. In short, 

 it is more like a femui'. The bones of monl-eys difler from those of man and the higher 

 apes by their greater hghtness. The cavity in the shaft is relatively larger and reaches 

 nearer the ends. 



Cakxivora. I have examined the l)oncs of the dog, lion, otter and sea otter. 'So de- 

 tailed description is necessary. The hiunerus and femur are more alike than in man and 

 the apes, the neck being relatively longer in the humerus and shortei' in the femur than 

 in the latter order. There is the same general plan in humerus and femur. The head 

 of the latter shows a somewhat greater solidity than in the forniei". This diftei'ence was 

 especially marked in the dog and hardly perceptible in the sea otter. This animal was 

 chosen in order to ascertain whether the bones present any resemblance to those of the 

 seal. Unfortunately, I could examine but a single sea otter and the bones proved imma- 

 ture and consequently unsatisfactory, for t3'pical structure is usual!)' evident only after 

 the nnion of the epiphyses. 



PiNKiPiCDiA. The bones of the seal are very interesting. The section of the hu- 

 merus (fig. *.)) passes through the head and the inner' tuberosit}^ It shows plates leav- 

 ing both sides of the shaft and tending towards the middle. Others pass into the head 

 from below. The line of the epiphysis of the head is well marked and pi-obably the line 

 obliquely cutting off the tuberosity marks the epiphj'sis also. The head is of a light, 

 round-meshed structure. The greater part of the tuberosity is taken up by plates, ra- 

 diating from two solid masses, situated, respectively, on the U[)per and outer border, which, 

 meeting at its outer extremity, form with the attached base a triangle, inside of which is 

 some light, spongy tissue. The femur (fig. 10) is by no means very different, but less 

 distinct. It shows a head of no greater solidity than the humerus. In both bones we 

 find a structure differing from any that we have yet seen, consisting of broad, relatively 

 thick plates with large spaces between them, which appears to be a generic peculiarity. 

 This description is made from bones of the P. vitulina, but the figure of the femur is 

 taken from the P. Oroenlandica which corresponds strikingly. The humerus in Otaria 

 jidiata shows a denser structure in the head and the characteristic structure of the seal is 

 less evident, though there is an approach to it. As above stated, the bones of a young 

 sea otter showed no trace of this peculiarity. 



Cetacea. I have examined bones of small wliales fifteen or eighteen feet long-, 

 proljablythe GloMcephalus ??if?«s, and also of ^xtrpoiscs. The section (fig. 11) embraces 

 the Avhole humerus. The denser, spongy tissue of the head is distinguishable. Plates 

 from the thick inner side run into it, and then there is a beautifully marked decnssation 

 at the upper end of the bone of plates from cither side. The highest ones from the 

 outer side run to the top of the bone. The tuberosity is of lighter texture. The thick- 

 ening of the solid parts on each side near the middle of the bone is even more marked 

 in a similar section of a young porpoise. The structure is very dense, and consists of 

 thin plates arranged very closely together. It seems characteristic. 



Ungulata. I have examined bones of the horse, moose, gazelle, caribou, sheep, goat 

 and harteheest (an African antelope). The four first-mentioned species differ from the 

 last-mentioned three in having the cancellated tissue prolonged much further into the 



' This section tlirough tlie inner tnberosity shows, T one throngli tlie outer, owing proljnljly to llic curious for- 

 tliinli, a greater resemblance to the rest oX tlie series than uiation of the humerus in this animal. 



