

Henri de Lacaze-Dnthiers. 147 



section of the same journal. For some years after 1853, his principal 

 interest was in the Mollusca. In 1854 and 1855 he was engaged in 

 the study of Lamellibranchs ; the memoir on Anomia demonstrating 

 the fact that this somewhat aberrant form does not differ essentially 

 from other Lamellibranchs, and is in no sense transitional to the 

 Brachiopods; those on the generative organs and the organs of 

 Bojanus in the same group also contributing largely to the advance- 

 ment of the knowledge of this division of the Mollusca. In 1856 and 

 1857 appeared one of his best-known works, the classical account of 

 the anatomy and development of Dentalium. Some of the figures 

 published in the memoir on Bonellia (1858) have re-appeared in 

 almost every zoological text-book, while the papers on Plewrobramchw 

 and Haliotis (1859) are hardly less well known. During a visit to 

 Minorca, in 1858, he noticed an "ignorant fisherman" marking his 

 clothes with the "purple of the ancients." This event led to the 

 publication of the scholarly " Memoire stir la Pourpre " (1859), in 

 which, by the citation of classical authorities and in other ways, he- 

 established the fact that the purple was probably that which is pro- 

 duced in certain species of Murex and Purpura, by what is now 

 known as the hypobranchial gland ; and showed that the secretion 

 of the gland acquires its final colour by exposure to the sunlight. 

 A summary of this work appeared in vol. x of the " Proceedings " 

 of this Society. Lacaze-Duthiers returned to the same subject in 

 1896, in introducing to the readers of the "Archives" an archaeo- 

 logical memoir on the purple by M. Dedekind. 



The French occupation of Algeria was responsible for the appear- 

 ance, in 1864, of one of Lacaze-Duthiers' most celebrated works, the 

 " Historic Naturelle du Corail." A special administration having 

 been created for the affairs of Algeria, M. le Comte de Chasseloup- 

 Laubat, the head of the administration, bethought himself of the 

 interest which he had taken, in 1834, in the fishery of Ked Coral in 

 that locality, and decided that a scientific enquiry should be made on 

 the subject. The work was offered to De Quatrefages, whose 

 occupations did not permit him to undertake the task, and he 

 accordingly wrote, in 1860, to Lacaze-Duthiers, inviting him to study 

 the question. Lacaze-Duthiers accepted the oifer, and at once went 

 to Algeria, charged with an official mission to study the natural 

 history of Oorallium. The work occupied him for two years, and 

 the memoir which was its result, illustrated by beautiful figures 

 drawn by the author, immediately took a leading place in the 

 literature of the Alcyonaria. An admirable account is given of the 

 structure of Oorallium, including that of its skeleton, of the repro- 

 ductive phenomena, and of the metamorphosis of the larva, while 

 the practical aspects oi the question are treated with the author's 



