Henri de Lacaze-Duthiers. 149 



first to give a satisfactory description of the development of one of 

 the Zoantharian Corals, but the account therein contained of the 

 development of the theca and septa is indispensable to all students of 

 this group. 



In 1882, Lacaze-Duthiers published his account of Laura gerardice, 

 a remarkable type of parasitic Crustacea. This had involved a new 

 visit to Algeria, undertaken with the object of further elucidating 

 the structure of certain organisms which had aroused his interest 

 during the first visit; and among these objects Laura, of which a 

 preliminary description had been published in 1866, occupied a 

 foremost place. The difficulties to be overcome were not slight ; 

 and among them the principal one was to obtain a supply of the 

 Gerardia which forms the host of the parasite. The occurrence of 

 unbroken colonies of this large and fragile Antipatharian in any 

 locality shows that that spot has not been disturbed by the Coral- 

 dredgers ; and any fisherman who finds an uninjured colony of 

 G-erardia is careful to conceal the fact that he has discovered a bank 

 which may harbour the precious Red Coral. 



The investigation of this subject showed that Laura belonged to 

 an entirely new group of the Cirripedia, for which the name 

 Ascothoracida was proposed. The structural details described are of 

 great interest, and not least of all in offering a fresh illustration of 

 the tendency shown by the Cirripedia to exchange their normal life 

 as animals fixed to some inanimate body for a condition of parasitism. 

 The adaptations to a parasitic existence shown by Laura differ in a 

 striking way from those which have been evolved in other Cirripedes 

 which have independently acquired the same habit of life. Although 

 one or two other genera of Ascothoracida have more recently been 

 discovered (to one of which the name Petrarca has fitly been given), 

 Lacaze-Duthiers' account of the type-genus is still by far the most 

 complete that has appeared of any member of that sub-order. 



It has only been possible to touch on a few of Lacaze-Duthiers' 

 contributions to Invertebrate morphology. Besides the smaller com- 

 munications contained in the " Comptes rendus," from 1853 onwards, 

 there are the well-known larger memoirs on Vermetus (1860), 

 Brachiopods (1861), Ascidians (1874, 1877), Aspergillum (1883), 

 Testacella (1887), and others. 



His activity showed but little sign of slackening even towards the 

 close of his life. He published voluminous papers on Actinozoa in 

 1895, 1897, and 1900; while during t'he last decade there appeared a 

 beautifully illustrated account of the Cynthiidte of Roscoff, written by 

 him in collaboration with his former pupil, Professor Yves Delage. 



In the midst of his own researches, Lacaze-Duthiers found time 

 for establishing and carrying on the marine stations at Roscoff and 



