158 THE VOYAGE OF H.M.S. CHALLENGER. 



than in most birds. Of the thoracic ducts the left is the largest. There are a femoral 

 and two axillary glands ; also an extra pair of bronchial glands more than in the Loon or 

 Gull." I must content myself with adding, by way of comment on this passage, that 

 although carefully looked for, I was unable to recognise the presence of either axillary or 

 femoral lymphatic glands in any species of Penguin which I had an opportunity of 

 dissecting. 



v.— NEUROLOGY. 

 THE BRAIN AND SPINAL COED. 



The brain (PI. XTL figs. 1, 2, 3) and spinal cord of every species of Penguin closely 

 resemble those of other birds. Tlie somewhat unsatisfactory state of preservation of the 

 brain prevented me making a minute examination of the organ. I have, however, 

 appended accurate drawings of the exterior of the brain in one species of each of the 

 genera which I had an opportunity of dissecting.* 



The cranial nerves of the Penguins in respect of their distribution closely resemble 

 those of the Duck or Goose, and the latter being well known, I feel it unnecessary farther 

 to allude to them. 



The spinal cord in the Penguins, as in other birds, develops a large rhomboidal sinus. 



SPINAL NERVES. 



Of the spinal nerves, in accordance with the number of intervertebral foramina, there 

 are forty-two paii-s in every species of Penguin. At the same time it is right to state 

 that in the coccygeal region of Eudyptes chri/socome I could only distinguish four instead 

 of seven pairs. The small size of the posterior nerves doubtless prevented me from 

 recognising them in the midst of tissue so hardened by the preservative employed as to 

 render the recognition of minute structures extremely difficult. 



As usual, each of the spinal nerves divides into two branches, a dorsal and a ventral. 

 The dorsal branches are distributed to the dorsal spinal muscles, as well as to the skin of 

 the back. The ventral branches present the arrangement described below. 



Cervical Nerves. 



The cervical nerves are fourteen in number. The anterior divisions of the upper 

 twelve appear in the dissection of the neck after passing from between the lateral and 

 inferior cervical muscles. They do not unite to form a plexus, but after supplying 

 numerous branches to the spinal muscles, reach the panniculus carnosus, which, together 



' Por tlie brain of Aptenodytes I am indebted to the kindness of Mr. Forbes, prosector to the Zoological Society, 

 who kindly removed it from a specimen which died in the menagerie of that society. The other drawings are from 

 Cliallenger specimens. 



