92 



393. The maxillary and mandibular arches of a Piked Dog-fish. 



Presented by Mrs. Robinson. 



Family Scyttiidee. 



394. A chain of the dried bodies of the vertebrae of a Spotted Dog-fish (Scyttium 



Canicula). 



A thin layer of ossific matter, in the form of a hollow cylinder expanded at both ends, has 

 been developed for each vertebra, in the capsule of the gelatinous notochord, constricting it 

 at intervals, but not obliterating it at any part. 



Hunterian. 



395. The upper jaw and teeth of a Spotted Dog-fish (Scyttium Canicula). 



The teeth in this genus present a triangular form with a large middle cusp, complicated, at 

 least in the young animal, with one or two small cusps on each side of its base ; the base is 

 always more or less furrowed longitudinally. 



Presented by Prof. Owen, F.E.S. 



396. The maxillary and mandibular arches of a species of Dog-fish (Scyttium Thylu- 



cina) from South Australia. Presented by Governor Grey. 



Family Nictitantes. 



397. The skeleton of a Tope (Galeus communis). It shows 20 ribs. The number 



of vertebrae is 140, of which 20 support short straight ribs : the haemal canal 

 begins to be formed at the 43rd vertebra. Hunterian. 



398. Four vertebral bodies of a Tope (Galeus communis}. 



The interspace between the terminal cones is filled by a compact ossification. The parapo- 

 physes have been removed from one side to show the shallow cavities against which their 

 bases are applied. The neurapophyses are supported by processes of the centrum, which arc 

 directly perforated by the motor roots of the spinal nerves. A distinct interneural piece is 

 wedged into each of the interspaces of the neurapophyses. 



Presented by Prof. Owen, F.R.S. 



399. A series of vertebrae of the Galeus communis. 



A terminal one has been vertically bisected to show the compact texture of the osseous 

 matter between the terminal cones. The neural cavities extend into the processes supporting 

 the neurapophyses. 



Mus. Brit. 



