CLELAND ON THE ANATOMY OF THE SHORT SUN-FISH. 179 



tendiuously from the tip of tho " clavicle :" its musciilar fibres are 

 very sparse, about three or four inches loii^, and are directed 

 downwards and bacliAvards, and prolonged into scattered tendinous 

 fibres Avhich are lost on the subcutaneous aponeurosis at the lower 

 and back part of the abdominal cavity. 



Besides these two insignificant muscles which cover only a trifling 

 part of its extent, there is nothing but a membrane betAveen the 

 abdominal cavity and the integument. 



Superficial iympTiatic and veins. — A very large lymphatic vessel 

 was observed in the subcutaneous aponeurosis, in the middle lateral 

 line. It extended nearly as far back as the posterior margin of the 

 dorsal fin, and there received a branch from above, and another from 

 behind, and continued its course directly dowTiwards till within a 

 little distance of the anal fin, then passed forwards, always becoming 

 broader, flatter, and weaker in the Avails, till, at the posterior margin 

 of the abdominal cavity, it was lost sight of, and probably poured its 

 contents into some of the lymphatic lacunae surrounding the viscera, 

 to be afterAvards described. 



The blood from the neighbourhood of the dorsal and anal fins 

 was returned principally by two superficial veins from each, AA'hich 

 continued superficial until near the middle lateral line. Each of 

 these veins received its branches from precisely the same district as 

 its neighbour, so that there was much crossing of branches, and 

 even the main trunks of the ascending pair crossed one another ia 

 contact, but always AAathout anastomosis, as far as was observed. 



Nervous system. — The brain and spinal cord of the sun-fish have 

 been described and figured by Arsaky {Be Piscium cerelro et 

 medulla spinalis. Salle, 1813, p. 5), whose work I have not as yet seen; 

 but his description is referred to, and a sketch given from his 

 drawing, in Cams' Comparative Anatomy. I have had an oppor- 

 tunity of verifying Arsaky's description as regards the extreme 

 shortness of the spinal cord. The spinal canal is occupied only by a 

 Cauda equina, which is made up of nerves Avhich can be traced up all 

 the way to within the cranial cavity, behind which there is no spinal 

 cord. 



On the other hand, as if to supply, to some extent, the gan- 

 glionic functions of the sj)inal cord, there is a pecuHar arrangement 

 outside the spinal canal, tln-oughout the whole length of tho abdo- 

 minal cavity. As each nerve emerges from the canal, it mal<es for 

 the abdommal aspect of the fibrous septum of the middle lateral 

 line, and presents a larger or smaller gangiiform enlargement, and 

 commmiicates with the nerves in front and behind it by a branch to 

 each, larger than its branches of distribution. Thus a cord runs 

 from the vagus to the first spinal nerve, from the first to the second, 

 and so on. In like manner also the trigeminal, branchial, and vagus 

 nerves appear to be united. 



