198 Mr. G. A. Boulenger on Fishes 



These facts seem to me to make more than probable the 

 supposition that at an earlier period the specimen had suffered 

 evisceration without the visceral mass being completely 

 detached. By the continuity of the ambulacral grooves of 

 two of the arms of the normal disk with one of the grooves of 

 the supernumerary disk a supply of food would be ensured to 

 the latter without seriously curtailing that of the former during 

 regeneration. In the paper just cited Mr. Dendy has shown 

 in how short a time the visceral mass may be regenerated, 

 twenty-one days being a sufficient length of time for regene- 

 ration to become so complete that " there is little to distin- 

 guish a regenerated specimen of this date from a normal 

 Antedon except the small size of the visceral mass and the 

 want of pigment upon it," 



The abnormal character and displacement of the anus and 

 the canal-like ambulacrum are not so easily accounted for; 

 but they are minor points, and do not appear to me to impair 

 the value of what has been advanced above. 



EXPLANATION OF PLATE VIII. 



List of reference letters. 



a. Anus. g'. Gut of supernumerary disk. 



a.g. Ambulacral grooves. to. Mouth. 



c. Abnormal ambulacrum. r.ic.v. Radial water-vessel. 



c.w.v. Circum-oral water-vessel. s.d. Supernumerary disk. 

 f.p. FunneWliaped projection of s.o. Skeletal ossicles. 



eupernumerary disk. w.t. Water-tubes. 



g. Gut. X. Ambulacral groove. 



Fig. 1. Oral surface of abnormal specimen of Antedon rosacea, X 5. 



Fig. 2. Aboral surface of abnormal specimen of A7ttedon rosacea, X 5. 



Fig. 3. Sagittal section through the normal and supernumerary disks^ 

 showing the point of union of the two, x 16. 



Fig. 4. Sagittal section of the supernumerary disk, passing through the 

 mouth and anus, X 16. 



Fig. 5. Sagittal section of the supernumerary disk, showing the funnel- 

 shaped projection traversed by the abnormal ambulacrum, X 16. 



XXX. — List of the Fishes collected hy Mr. E. W. Gates in the 

 Southern Shan States, and presented hy him to the British 

 Museum. By G. A. Boulenger. 



The collection made by Mr. Gates in a district previously 

 unexplored, so far as Fishes are concerned, proves of great 

 interest. It adds to our knowledge of the extension of species 



Studies from the Biological Laboratories of the Owens College, i. (1886) 

 pp. 299-312. 



