ON THE ZOOLOGICAL STATION AT NAPLES. 157 



I further examined the tails of several other Elasmobranchs in 

 search of an organ homologous with that of the skate, but without 

 success. In Torpedo ocellata, T. viarmorata, Mustelus laevis, Scyllium 

 canicula, Notidanus cinereus, Scymnus liclda, the tails of which I carefully 

 studied, I was unable to discover any trace of the structure so well de- 

 veloped in rays. The condition of the sacro-lumbar muscle in Squatina 

 angelus, however, is worthy of remark. Its outer part is quite different 

 in appearance from that nearest the vertebrae, being divided by connec- 

 tive-tissue septa into a number of longitudinal columns. The resemblance 

 to an electric organ is, however, purely macroscopical, an examination of 

 the more intimate structure showing no traces of change from ordinary 

 muscle. The matter, nevertheless, is worthy of further attention, and it 

 is interesting to note that this peculiar condition of the muscle occurs in 

 a form which is intermediate between the round (Selachoidei) and the 

 flat (Batoidei) members of the Elasmobranch group. 



Another question which I set myself to elucidate was in how far the 

 electric organ of the skates, which varies considerably in the different 

 species in form and size, and relation to surrounding muscles, might be 

 made a character in determining species, but I have not yet suflBciontly 

 studied my notes to justify the expression of an opinion. 



In concluding my report, I take the opportunity of expressing my 

 deep gratitude to the Committee for their kindness iu affording me sucla 

 splendid facilities for prosecuting my research, and further I desire to 

 convey my sincerest thanks to Dr. Dohrn and all the members of the 

 staS" at the Zoological Station for their unfailing courtesy and the willing 

 help which they were always ready to render. 



III. Beport on the Occupation of the Table, hy Professor R. J. Anderson. 



I arrived in Naples on June 4. The table was furnished immediately 

 with instruments and preserving fluids. I decided to examine the 

 myotomes in a great number of fishes. The importance of the subject 

 at once appears. The muscles are less complex than in other vertebrates, 

 the primitive arrangement is largely maintained, and we have, to start 

 with, the works of Cuvier, Meckel, Miiller, and Stannius, and of Owen, 

 Schneider and Humphry, together with the special work of Vetter, Fiir- 

 bringer (whose work has some bearing on the subject), Albrecht, Goette 

 and others. English readers are most familiar with the myological work 

 of Humphry through his contributions to the English Journal of Anatomy 

 and his special work on ' Myology.' The whole subject is, however, so 

 difiBcult that we require abundance of facts to make any certain advance. 

 I have, therefore, measured and noted the arrangement of the metamers 

 in a great many fishes. I have made no reference to the embryological 

 conditions. The general condition of things is to be found in Miiller's 

 myxinoid fishes. His description is adopted by everyone, and my work 

 goes mainly to tease out some of the observations of that anatomist. 



The fibrous partitions that separate the metamers are not planes, and 

 the line of outcrop is a curved line. The number of the metamers, their 

 thickness, and the number and character of the bendings all vary. The 

 distance to which the anterior metamers reach in the cranium is not 

 constant. I have, then, recorded — 



1. The number of metamers. 



2. The exact length of each segment of a number of metamers, as it 

 appears on the surface. 



