234 ^^^^ Irish Naturalist, November, 



REVIEWS. 



OUR NATIVE SEA SLUGS. 



A Monogrraph of the British Nudibranchlate IVIolIusca: 



with Figures of the Species. Part VIII (Supplementary). Figures 



'by the late Joshua Alder and the late Ai.bany Hancock, and 



Others. Text by Sir Charles Euot, M.A., D.C.L, LL.D., 



K.C.M.G., C.B. London, Ray Society, 1910. 4to. Pp. 1-198. 



Plates I.-VI II. 



This part just published forms a Supplement to the Monograph of 



the British Nudibranchiate MoUusca by J. Alder and A. Hancock 



published in seven parts in the years 1845- 1855. It is based, Sir Charles 



Eliot tell us, on a selection from some figures of Nudibranchs that 



Alder and Hancock had prepared for a Supplement to their Monograph, 



and which had been deposited in the Hancock Museum at Newcastle- 



on-Tyne. New figures drawn from living specimens oi Doris testiidinaria^ 



D. maculata^ Pleurophyllidia Loveni, Lofuanottis Genei, Cenia Cocksi, and 



Ciimanotus Beaumont i 'are added, also figures of Laniellidoris htteocincta, 



and a few figures giving details of anatomy and dentition. 



The text divides naturally into three sections. The first section, con- 

 sisting of ninety-two pages or nearly half of the part, is devoted to a 

 general discussion of the Nudibranchiata under the headings variation 

 and distribution, nomenclature, bionomics, embryology and larval stage 

 anatomy, classification, affinities and relationships The second section 

 contains descriptions of certain genera and species, and the third a 

 synopsis of families, genera, and species of the nudibranchiate fauna 

 of the British Isles, a Bibliography and an Index. 



After a short account of specific variation as exhibited in the Nudi- 

 branchiata and its supposed causes, the author discusses at considerable 

 length the distribution of these animals in the North Atlantic and 

 neighbouring seas. 



Under the heading Bionomics, an interesting account of their life- 

 histor}' and habits is given ; several examples of protective resemblance 

 and warning coloration are mentioned ; and the evidence brought 

 forward in recent years by Grosvenor and other observers in favour of 

 Strethill Wright's views, that the nematocysts (thread-cells) of certain 

 nudibranchs are not developed in the body of the nudibranch but are 

 derived from the various hydroids, &c., on which it feeds, is here 

 referred to. 



The most important portions of this work are probably those headed 

 "anatomy," "classification," " affinities and relationships." Very com- 

 plete descriptions of the anatomy of Doris tuherciilata and Aeolidi 

 papulosa are given, these species being selected on account of their 

 considerable size and of being common on our coasts ; they also 

 represent the types of structure characteristic of the Holohepatica and 

 Cladohepatica respectively, the two tribes into which the author thinks 



