9 Bibliography. 



fully describes the Nauplius and Cypris stages, and also places Lilljeborg's discovery of the 

 larval males, whose nature he rightly surmises, upon a firm basis. 



In 1873 and 1874 appeared a series of papers by Giard 8, 11 and 12 and Kossmann 

 (9 and 10), whose chief merit appears to me to be the recognition of the orientation of the 

 body and the position of the mesentery as furnishing the clue to the inter-relationship of the 

 parasites. But I cannot accept a deal of Kossmann's systematic work, and there is no trace 

 of a suspicion in the work of either Kossmann or Giard of the complicated life-history subse- 

 quently discovered by Delage. 



In 1S75 Dohrn (13) in his well known essay on Vertebrate descent advanced the view, 

 which despite Deeage's arguments I believe to be correct, that the Rhizocephala are fixed to 

 their hosts by a part of the body corresponding to the stalk of the Cirripedia. This view, 

 based on a comparison of the Rhizocephala with Anelasma, might belong, according to the 

 rules of priority to Kossmann (10), who admits that he owed to Professor Dohrn the inspira- 

 tion to study Anelasma and the possession of his material for the study. His possession of 

 the theory, however, is not so secure; for in his first paper (9 p. 34) he announces, and in 

 his second 10 p. 11) reaffirms the discovery of a tube in Sacculina hians , running from 

 the ring of attachment (Russel) and opening in the mantle cavity, which he takes to be 

 the remnant of the gut, an interpretation which, if it were real, would be quite disastrous to 

 his theory that the ring of attachment is homologous to the stalk of the Cirripedes, and would 

 confirm the previously accepted view that the ring of attachment equals the mouth. 



But this theory of the relationship of Anelasma to the Rhizocephala, which appears to 

 be suddenly revealed in Kossmann's paper, was accurately sketched by Lilljeborg (4 p. 82), 

 thirteen years previously. The Norwegian naturalist 's essay is written in French, but this can 

 hardly account for Kossmann's neglect of it. 



In 1884 Deeage's monograph (14 appeared containing a very complete exposition of 

 the anatomy and life-history of Sacculina carcini (Thompson). In this extremely interesting 

 work the author makes most important additions to our knowledge of the general anatomy, 

 describing the nervous system for the first time; but the discovery which attracted the wonder- 

 ing attention of all naturalists was the method of fixation of the Cypris larva upon an hair 

 on any part of the host's body, except on the ventral surface of the abdomen where the adult 

 Sacculina is situated, the migration of the cells of the larva into the crab's body where they 

 establish the system of roots, and the subsequent appearance upon the lower part of the crab's 

 intestine of the Sacculina interna which afterwards becomes evaginated as the adolescent Saccu- 

 lina externa. Delage observed in numerous cases the fixation of the Cypris larvae and their 

 subsequent transformation leading to the so-called Kentrogon stage, but he did not observe 

 the actual passage of the cells into the crab's body, because the larvae under his observation 

 died soon after the assumption of what he terms the Kentrogon stage. There is therefore a 

 lacuna in Delage's account of the life history between the fixation of the Cypris larva and 

 the appearance of the parasite within the body of the crab, fixed upon the intestine roughly 



