100 Mr. Thompson on the Mollusca of Ireland. 



Several specimens of different size dredged some years 

 ago in Dalkey Sound, on the coast of Dublin, by R. Ball, Esq. 

 The species is named after my friend, than whom no one in 

 Ireland does more to advance the science of natural history. 



Holothuria Drummondii, mihi. 



H. of an olivaceous and white colour, with light brown suckers, 

 which are very numerous on the angles, from G to 12 in each trans- 

 verse irregular row ; when contracted, tentacula long, pedicled, trifid, 

 plumose, purple. 



Lengtli 10 inches. 



After having been kept in spirits for a short time, it ap- 

 pears angular, corrugated, the corrugations smooth; a few 

 suckers between them. 



The specimen was dredged in Belfast Bay, in the month 

 of June, by Dr. J. L. Drummond, who drew up the following 

 description from the living animal : 



"Bangor, June 27, 1839. Holothuria dredged yesterday 

 of an olivaceous and white colour; at first, the shape of a 

 lemon, and nearly as large as a middle-sized one ; today, ten 

 inches long, contracting itself slowly in various places, but 

 has not yet shown its tentacula. It has five broad longi- 

 tudinal bands of tubercle-like suckers running from end to 

 end ; these have four in each transverse row ; suckers light 

 brown ; down the middle of each of the five series a whitish 

 band extends ; spaces between the belts of suckers of a 

 blueish- white, with numerous irregular narrow transverse 

 whiter lines of various breadth." 



Holothuria Hyndmani, mihi. 



H. white, 5 -angled, skin smooth, a double close row of large 

 (non-retractile?) suckers on each angle; tentacula 10, sessile, white, 

 plumose. 



Length 2 inches. 



Dredged in Belfast Bay, by my friend Mr. G. C. Hynd- 

 man, a well-informed and zealous naturalist, to whom it is 

 dedicated*. 



* " Holothuria brunnea, Forbes MS. 



" H. brown, angulated, suckers 6 to 8 in each row, tentacula long, whitish, 

 pinnated towards their extremities. Forbes." 



This minute Holothuria, generally under an inch in length, is the most 

 common species taken by dredging in the loughs of Strangford and Belfast. 



