i9°7' Colgan. — Marine Mollusca of ' Lamb ay. 35 



was brought up to a total of 117 species. This happens to be 

 precisely equal to the total yielded me \>y a close examination 

 on many days and at all seasons of the year of the famous 

 Portmarnock strand, the classic ground pa?- excellence of 

 Co. Dublin conchology ; it is no less than 23 species in 

 excess of the number I have hitherto succeeded in finding on 

 the Rush or mainland shore directly opposite to Lambay. So 

 far, then, from being poor, the marine molluscan fauna of the 

 island deserves to rank as exceptionally rich, judged by the 

 Co. Dublin standard. 



The most interesting item in the list which follows is un- 

 doubtedly Runcina Hancocki, discovered by Mr. Wollaston 

 among seaweeds on the S.W. shore. This is an addition to 

 the marine mollusca of East Ireland, the only other Irish 

 record extant being one for Valentia Harbour, where the 

 species . was found by Mr. F. W. Gamble in 1895 (Proc. 

 R. 1. Acad., (3), vol. v., 1900). Two others of the Lambay 

 species here listed, Odostomia turrita and Rissoa calathus, the 

 latter regarded by some authorities as a variety of R. reticulata, 

 are new to Co. Dublin, and three others, Cerithiopsis 

 tubercularis, Odostomia rissoides, and Mytilus phaseolinus, were 

 first recorded for the county in the issue of this Journal for 

 July, 1906. In addition to these, several species, rare for Co. 

 Dublin, are here first put on record for L,arubay — i.e., Tectu?a 

 testudinalis, Trochus miltegranus, Rissoa puuctu? a, R. i?ico?ispicua, 

 R. soluta, R. semistriata, fejfreysia diaphana. Odostomia pallida, 

 O. insculpta, Philifie punctata, P catena, Pecten tigrinus, and 

 Ttllina donacina. 



No previous attempt appears to have been made to catalogue 

 the L,ambay marine mollusca, and the published references to 

 this section of the island fauna are very few. William 

 Thompson, the accomplished author of the " Natural History 

 of Ireland," paid at least one visit to Iyambay (in June, 1838), 

 and collected there one Chiton, C. ruber, entered in his MS., 

 and three Nudibranchs, sLolis papulosa, Doris bilamellata, and 

 Goniodoris ?iodosa, which are duly recorded in vol. iv. of his 

 History. Of these four species only one, SE. papulosa, was 

 observed by us in Easter last, so that Thompson's records 

 (here entered in square brackets) raise the total of known 

 L,ambay mollusca from 117 to 120. 



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