202 

 2. Choniostoma Hansenii Giard and Bonnier (continued). 



Funre 



2 a. Adult female, X --V*- 



2 b. Small female, X '"A. 



2 c. Ovisac, X -V*- 



2 d. Head of an adult female, X 130. 



2 e. Part of the skin of the ventral side outside the head of a small female, X 130. 



2 f. Genital area of an adult female, X 128. 



3. Mysidion commune n. gen., n. sp. 



3 a. The contents of the marsupium of an Erythrops s rrafus G. 0. S. seen from below and con- 



sisting of the female parasite with its seventeen ovisacs, X 12. 

 3 b. Another female with its ovisacs from Er. serratus seen from above (the head situated on the 



dorsal side and its front turning backward), X 25; r/. maxillipeds. The contents indicated 



only in three of the thirteen ovisacs. 

 3 c. Four ovisacs of another female, X 25. In the largest ovisac only a small part of the con- 

 tents, namely six larvaj, are drawn. 

 3 d. Male, X 25. 

 3 e. Posterior half of the ventral surface of female, X '42 ; e. skeleton surrounding one genital 



aperture; r. transition between the receptaculum seminis and one of its ducts, s. spermatophores. 

 3 f. Left genital aperture with its lips, muscles and the surrounding skeleton seen from below, X 1 90. 

 3 g. Male seen from below, X 258 ; q. spermatothecas. The hair-covering of the trunk drawn 



only on one side. 

 3 h. Another male seen from left side, X 258 ; .9. frontal thread, t. part of a marsupial plate of 



the host, X. conical eminence on the dorsal side of the head. 

 3 i. Very small pupa seen from below, X 188; x. outline of a mouth (?) beneath the skin of the 



pupa. — This and all the other figures of this parasite are drawn from animals taken on 



Erythrops serratus G. 0. S. 



PLATE XII. 



1. Mysidion commune n. gen., n. sp. (continued). 



1 a. Head of female, X 182; a. antennula, u. process of unknown nature (perhaps stiffened 

 viscous substance on the opening of the gland producing it). 



1 b. Pupa with dorsal thread, X 25. (The same enlargement as in fig. 3b — 3d on pi. XI.) 



1 c. Pupa seen obliquely, X 182; a. (misscript fore.) antenna, f. maxilla, g. maxilliped, r. skeleton 

 surrounding the future genital aperture, t. (misscript for a.) antennula, u. basal part of the 

 dorsal thread shining through the animal, v. distal part of the thread, x. eminence at the 

 mouth of the pupa stage, y. mouth of the pupa stage, i/. chitinous lists on the side of the 

 rostrum of the pupa. The mouth and the maxillulae of the young female are seen at the 

 anterior end of the animal. 



1 d. Very young female in possession of characters which it loses afterwards, X 1 82 ; a. (misscript 

 for c.) antenna, r. skeleton surrounding the future genital aperture, t. (misscript for a.) anten- 

 nula, u. basal part of the dorsal thread, v. distal ' part of the dorsal thread, x. odd ventral 

 process situated at the place of the mouth of the pupa stage, z. body of unknown nature. 



