STRANDED AT LONGNIDDRY. 231 



followed closely that of man ; and he refers to brachio-cephalic, left carotid, and 

 left subclavian arteries ; and Malm observed a similar disposition in his 

 Balwnoptera. It seems, therefore, that these great arteries have a similar mode 

 of origin in different species of Finners. In Delphinus and Globiocephalus, how- 

 ever, the great arteries arise in the form of two brachio-cephalic arteries, and 

 the left posterior thoracic arises usually quite independently ; but as I have on 

 former occasions * described these arrangements, I need not in this place enter 

 into any further details. 



It will be necessary now to give an account of the very remarkable monili- 

 form tube, which I have referred to in the description of the intestine of the 

 adolescent animal. It was found along the entire length of the mesenteric 

 attachment of the gut, and extended back along the rectum. It exhibited an 

 alternating series of dilatations and constrictions, which varied in their dimen- 

 sions in different parts (Plate VIII. figs. 32, 33). The dilatations were some- 

 times globular, at others ovoid in form, and in some cases were flattened on 

 their surfaces. The largest measured as much as 1 foot 6 inches in transverse 

 external circumference, whilst the smallest were only 8 or 9 inches. When the 

 dilatations were ovoid the elongation was mostly in the direction of the long 

 axis of the tube, in which direction the circumference of the dilatation was 

 therefore somewhat greater. The constrictions also varied in size, the smallest 

 being about 4 inches in external circumference, the largest 1 or 2 inches more. 

 The tube possessed very strong and dense walls, which varied in thickness in 

 different parts. In the larger dilatations the thickness was as much as 1^ inch, 

 but in the smaller not more than ^ inch. The walls were white, tough, and 

 very resisting. Examined microscopically, the tissue which composed them 

 was seen to be chiefly the white fibrous, but mingled with it were elastic fibres. 

 The inner surface of the wall presented a corrugated appearance, owing to the 

 presence of a number of permanent, circular folds, wrinkles or ridges, which 

 passed quite around the inner surface of the tube (fig. 33). In many places 

 these folds were situated close together ; but elsewhere they were separated by 

 intervals in which the inner wall of the tube was comparatively smooth. These 

 ridges were in part formed of a folding of the lining membrane of the tube, and 

 in part of the fibrous tissue of the wall. Some of the largest of these folds 

 projected as much as 1 inch, or even more, into the lumen of the tube, and as 

 this projection was carried all round the inner wall, the lumen was necessarily 

 much constricted in these localities, and in the smaller divisions the bore was 

 sometimes reduced to a hole in the middle of the fold less than 1 inch in 

 diameter, whilst on each side of it the tube might perhaps dilate into a space 

 2, 3, or more inches in its diameter. Hence the dilated and constricted 



* British and Foreign Medico-Chirurgical Review, October 1862, p. 479, and Journal of Anatomy 

 and Physiology. Vol. ii. p. 66. 



