Is THE VOYAGE OF H.M.S. CHALLENGES. 



However, it would be rather premature to draw the conclusion that the Crustacea 

 Podophthalmata of the deep-sea do not suffer from parasitic Cirripedia. 



Although Cavolini 1 (1787) published recognisable figures of the full-grown animals, 

 and of the larva, and also showed the great resemblance of these larvse to those of 

 Cyclops; though different forms of these curious parasites were known long before 1854, 

 from the papers of Eathke 2 and others; 3 though Thompson, 4 in 1836, speaks of a 

 concealed affinity between these parasites and the Cirripedia, Darwin, as their true 

 Cirripedial nature was not yet proved, could not take notice of them in his Monograph. 

 Steenstrup 5 (1854) and Lindstrom 6 (1855) were, after Thompson, the first who suggested 

 in their papers the relation of these parasites with the Cirripedia ; but Lilljeborg 7 (1861) 

 no doubt has the merit of having been the first to base this relation on anatomical grounds. 

 Fritz Mtiller 8 (1863) (in the case of Lernceodiscus and Peltogaster) then showed that the 

 second larval form of these parasites in almost every respect corresponds to the Cypris-larva 

 of the Cirripedia, and though the same stage for Sacculina has not yet been observed, since 

 his discovery the affinity of these highly degenerated parasites with the true Cirripedia has 

 no longer been doubted. Lilljeborg regards them as true Cirripedia, and proposes for them 

 the name of Cirripedia Suctoria. Fritz Muller, on the contrary, wishes to consider them as 

 a distinct order of Crustaceans, which he calls the Rhizocephala, and which form an equi- 

 valent group to the nearly related Cirripedia. Since then our knowledge of these aberrant 

 forms has not much increased. A large number of species has been added to those known 

 to Lilljeborg, and the number of genera has also been considerably augmented. 9 The 

 most important contribution to our knowledge of the anatomy of these curious parasites 

 is contained in the papers of Kossmann. I have already pointed out (page 13) that this 

 author considers Anelasma squalicola to be a link uniting the Cirripedia Suctoria with the 

 true Cirripedia Thoracica — a view which I think requires confirmation by exact observation. 



In 1865, Prof. H. de Lacaze-Duthiers published a provisional description of a para- 

 sitic animal of the Crustacean class, which he called Laura gerardice, and which was 

 considered by him to belong to the Cirripedia. 10 On this same animal an elaborate 

 memoir was published by the same author in 1882. 11 This very interesting parasite 



1 Cavolini, F., Memoria sulla generazione dei Pesci e dei Grancbi, Napoli, 1787. 

 - Rathke, Nova Acta Acad. Caes. Leop. -Carol. Nat. Cur., xx. p. 244, 1843? 



: Diesing, Krbyer. * Thompson, J. V., Tlie Entomological Magazine, iii. 1836. 



1 Steenstrup, J. J., Bemaerkninger om Slaegterne Pachybdella, Dies, og Peltogaster, Rathke, Oversigt o. d. K. I). 

 Vid. Selsk. Forhandl., 1854. 



Lindstrom, G., Om larven til en art af Slagtet Peltogaster, Ofversigt k. Vetensk.-Akad. FSrhandl, 1855. 



7 Lilljeborg, W., Les genre Liriope et Peltogaster, Upsala, 1859-60. 



* .Muller, Fr., Die zweite Entwickelungstufe der Wurzelkrebse, Archivf. Naturgesch., Jahrg. xxix. 1863. 



9 So by the papers of Anderson (Arm. and Mag. Nat. Hist., ser. 3, vol. ix, 1862), Semper (Zeitschr.f. wiss. Zool., Ed. 

 xiii., 1863), M. Sars (Nyt Magaz. f. Naturvid., xvii., 1870), Kossmann (Arbeit, zool. zoot. Instit. Wurzburg, i., 1872-74), 

 Kichiardi (Atti. d. Socist Tosc. d. Scienz. Natural, L, 1874), G. 0. Sars (Arch. f. Math, og Naturvid., iv., 1880), and others. 



10 Comptes rendus, t. lxi., 1865. 



" Histoire de la Laura Gerardiai, MJm. Acad. Sci. Paris, t. xlii., Paris, 1882. 



