CETACEA. 



the head, immediately under the s>kin, and 

 common adipose membrane. These cells re- 

 semble those which contain the common fat in 

 the other parts of the body nearest the skin. 

 That which lies above the roof of the mouth, 

 or between it and the nostril, is more inter- 

 mixed with a ligamentous cellular membrane, 

 and lies in chambers whose partitions are per- 

 pendicular. These chambers are smaller the 

 nearer to the nose, becoming larger and larger 

 towards the back part of the head, where the 

 spermaceti is more pure. 



" This spermaceti, when extracted cold, has 

 a good deal the appearance of the internal 

 structure of a water melon, and is found in 

 rather solid lumps. 



" About the nose, or anterior part of the 

 nostril, I discovered a great many vessels, 

 having the appearance of a plexus of veins, 

 some as large as a finger. On examining them, 

 I found they were loaded with the spermaceti 

 and oil ; and that some had corresponding 

 arteries. They were most probably lym- 

 phatics ; therefore I should suppose, that their 

 contents had been absorbed from the cells of 

 the head. We may the more readily suppose 

 this, from finding many of the cells, or cham- 

 bers, almost empty; and as we may reason- 

 ably believe that this animal had been some 

 time out of the seas in which it could procure 

 proper food, it had perhaps lived on the super- 

 abundance of oil. 



" The solid masses are what are brought 

 home in casks for spermaceti. 



" I found, by boiling this substance, that 

 I could easily extract the spermaceti and oil 

 which floated on the top from the cellular 

 membrane. When I skimmed off the oily 

 part, and let it stand to cool, I found that the 

 spermaceti crystallised, and the whole became 

 solid; and by laying this cake upon any 

 spongy substance, as chalk, or on a hollow 

 body, the oil drained all off, leaving the sper- 

 maceti pure and white. These crystals were 

 only attached to each other by edges, forming 

 a spongy mass ; and by melting this pure 

 spermaceti, and allowing it to crystallise, it 

 was reduced in appearance to half its bulk, 

 the crystals being smaller and more blended, 

 consequently less distinct. 



" The spermaceti mixes readily with other 

 oils, wh.le it is in a fluid state, but separates 

 or crystallises whenever it is cooled to a certain 

 degree ; like two different salts being dissolved 

 in water, one of which will crystallise with a 

 less degree of evaporation than the other ; or, 

 if the water is warm, and fully saturated, one 

 of the salts will crystallise sooner than the 

 other, while the solution is cooling. I wanted 

 to see whether spermaceti mixed equally well 

 with the expressed oils of vegetables when 

 warm, and likewise separated and crystallised 

 when cold, and on trial there seemed to be 

 no difference. When very much diluted with 

 the oil, it is dissolved or melted by a much 

 smaller degree of heat than when alone ; and 

 this is the reason, perhaps, that it is in a fluid 

 state in the living body. 



' If the quantity of spermaceti is small in 



proportion to the other oil, it is, perhaps, nearly 

 in that proportion longer in crystallising ; and 

 when it does crystallise, the crystals are much 

 smaller than those that are formed where the 

 proportion of spermaceti is greater. From the 

 slowness with which the spermaceti crystallises 

 when much diluted with its oil, from a con- 

 siderable quantity being to be obtained in that 

 way, and from its continuing for years to crys- 

 tallise, one would be induced to think, that 

 perhaps the oil itself is converted into sper- 

 maceti. 



" It is most likely, that if we could dis- 

 cover the exact form of the different crystals 

 of oils, we should thence be able to ascertain 

 both the different sorts of vegetable oils, much 

 better than by any other means ; in the same 

 manner as we know salts by the forms into 

 which they shoot."*] 



ORGANS OF GENERATION. The organs con- 

 cerned in the reproduction of the species do 

 not exhibit the same type of conformation in 

 the Phytophagous as in the Zoophagous species. 

 In the former the mammae are pectoral, in the 

 latter inguinal or rather pudendal, since they 

 are situated on each side of the vulva : in both 

 orders their number never exceeds two. The 

 vulva, which resembles in its form that of the 

 Ruminants, presents nothing peculiar in its 

 structure. 



The penis is attached to the rudimental 

 bones of the pelvis ; in the Phytophaga the 

 glans is complicated, but in the Zoophaga it is 

 of a simple elongated fusiform shape : in all 

 the species it is provided with a prepuce. 



[According to Hunter, the parts of generation 

 in both sexes of this order of animals come 

 nearer in form to those of the Ruminants than 

 of any others; and this similarity is, perhaps, 

 more remarkable in the female than in the male; 

 for their situation in the male must vary on 

 account of the modification of the external 

 form of the body. 



The testicles (a, a,fgs. 277, 278) retain the 

 situation in which they were formed, as in 

 those quadrupeds in which they never come 

 down into the scrotum. They are situated 

 near the lower part of the abdomen, one on 

 each side, upon the two great depressors of the 

 tail. At this part of the abdomen, the testicles 

 come in contact with the abdominal muscles 

 anteriorly. 



The vasa deferentia (c, c) pass directly from 

 the epididymis (b, 6) behind the bladder (d, rf) 

 or between it and the rectum (e) into the 

 urethra (f) ; and there are no bags similar to 

 those called vesiculae seminales in certain other 

 animals. 



The structure of the penis is nearly the 

 same in them all, and formed much upon the 

 same principle as in the quadruped. It is 

 made up of two crura (g, g\ uniting into one 

 corpus cavernosum, and the corpus spongiosum 

 seems first to enter the corpus cavernosum. 

 In the Porpoise, at least, the urethra is found 

 nearly in the centre of the corpus cavernosum ; 

 but towards the glans seems to separate or 



* Philos. Trans. 1787, p. 390. 



