IXXX rROCEEDIXGS OF THE 



Conchology. On the motion of the Chairman a vote of thanks 

 was awarded to Mr. Somerville for his gift. 



Mr. David Robertson, F.L.S., F.G.S., sent for exhibition a 

 specimen of the Heart Urchin, Anijthidotus cordatus, Penn., a 

 common species on the sandy shores of the Firth of Clyde ; 

 and, in a short paper, he comanunicated the result of experi- 

 ments made by him with the view of determining the seat of 

 secretion of the mucus which the animal possesses the power 

 of discharging. * 



Mr. Somerville made some remarks on the Echinoldea or 

 Sea-Urchins, and gave an account of the morphology of the 

 various British genera, pointing out the distinguishing features- 

 on which their classification is based. These he illustrated by 

 means of coloured diagrams, showing on an enlarged scale the 

 structure of the typical species. 



Mr. Thomas King read an interesting paper on "The Origin 

 of our Food-Plants." 



23rd February, 1886. 



Dr. James Stirton, F.L.S., President, in the Chair. 



Mr. Thomas Scott, Corresponding Member, sent for exhibition 

 a glass jar containing sea-water in which many of the free 

 larvae of Balamis balanoldes could be seen moving rapidly 

 about. 



Mr Scott also sent specimens of Lej^taspidea hrevipes, Bate 

 and Westwood, an Isopod of Avhich three examples were 

 obtained by him in 1884, among material dredged from a depth 

 of about ten fathoms, muddy bottom, in the Clyde near Fort 

 Matilda, Greenock. All that can apparently be learned regard- 

 ing the distributid'n of this species, is as follows: "We are only 

 acquainted with a single individual of the single species upon 

 which we have established this genus,— two or three specimens 

 having been taken by Mr. Robertson at Cumbrae to whom we 

 are indebted for it."t The length is stated by Bate and West- 

 wood to be "one twentieth of an inch," but one of the specimens 

 taken by Mr. Scott rather exceeded that measurement. X 



Mr. Scott also sent specimens of an apparently undescribed 

 species of Anceus, three or four of which were obtained in the 

 same locality and about the same time as the Lex)iafipidea 

 hrevipes above referred to. He had at first been inclined 

 to refer these to A. maxillaris \ but, on examination, the 

 mandibles were found to differ materially from those of that 

 species, and of all the species described in Bate and West- 

 wood's British Sessile-eyed Crustacea. They rather resembled 



* Transactions, i. 290. 



t Bate and Westwood, British Sessile-eyed Crustacea, vol. ii., p. 333. 

 ij: This species has &ince been found by Mr. Scott to be of frequent occurrence 

 both in Lochfyne and in Kothesay Bay. 



