218 PROFESSOR TURNER'S ACCOUNT OF THE GREAT FINNER WHALE 



modified, horny, epithelial cells of the baleen plates were developed. The 

 vascularity of the folds and of the papillae has also been recognised by these 

 anatomists, but no exact description of the arrangement of the vessels has 

 as yet been given. 



The fresh condition of the baleen in the B. rostrata led me to think that it 

 might be possible to inject its papillae, and to obtain a more complete view of 

 the arrangement of their vessels than had yet been described. I accordingly 

 carefully detached the entire palatal mucous membrane, with its baleen wreaths, 

 from the upper jaw; and after introducing injecting pipes into several of the 

 palatine arteries, I succeeded with the aid of my assistant, Mr Stirling, whose 

 skill as a minute injector is so well known, in injecting the vessels of the baleen. 

 But before proceeding to describe their arrangement, it will be necessary to speak 

 of two other groups of papillae, which appear hitherto to have been overlooked by 

 anatomists. When the surface of the palatal mucous membrane, situated be- 

 tween the bases of the transverse folds, was examined with a pocket lens, it was 

 found to be studded with short papillae, which fitted into clefts similar to those 

 already described (fig. 23), as extending into the intermediate substance from 

 its deep attached surface. These papillae we will call intermediate. Similarly, 

 when the sides of the transverse folds were also examined with a pocket lens, they 

 were seen to give origin to numerous minute papillae, which passed into minute 

 apertures in the inner wall of each of the laminae, produced by the cleavage of 

 the baleen plate at its base. These laminae were continuous with the cortical 

 layer of the plate to which they belonged, and their papillae may be called peri- 

 pheral or cortical. 



In the injected preparations, the following appearances were seen in vertical 

 sections (fig. 27). The palatal mucous membrane was highly vascular, and the 

 principal vessels ran parallel to the horizontal plane. They gave origin to 

 smaller vessels, which were distributed to the three groups of papillae. Those 

 which passed to the intermediate papillae, occupying the spaces in the attached 

 surface of the intermediate substance, did not enter the transverse folds or pulp 

 blades ; they were very slender, but formed distinct loops (fig. 27). The vessels for 

 the other papillae entered the transverse folds. Those destined for the peripheral 

 or cortical papillae formed a well-defined superficial network of small vessels, 

 which gave off, at intervals, capillaries which entered these papillae, and formed 

 loops in the usual maimer. The vessels for the elongated, filiform, tubular 

 papillae were considerably larger. As a rule, two entered the base of each papilla, 

 and extended along its axis into the tube. These vessels preserved their size 

 for a very considerable distance down the tube, and occasionally anastomosed. 

 They were easily recognised by the naked eye, both in vertical and transverse 

 sections of the plates and setae ; and it was in them that the blood was contained 

 which conferred on the baleen of B. rostrata its characteristic pink markings. 



