203 



Fi ure 2. Mysidion abyssorum n. sp. 



2 a. Head of female, X 182; a. antennula, e'. additional branch of the maxillula. 



2 b. Genital aperture and the surrounding skeleton of female, X 123; g. genital aperture, h. plate 

 formed of a kind of viscous substance and covering the lips of the genital aperture and the 

 skeleton behind them, i. stalks of ovisacs, the basal parts of which are confluent and form 

 the plate mentioned, k. hole (or very small thin-skinned area with minute holes) at the 

 anterior end of the skeleton. 



2 c. Male, 43. 



2 d. Very small male with frontal thread, X 43. 



2 e. Normal male seen from below, X 256; e. maxillula, q. spermatotheca, u. line of unknown 

 nature. 



2 f. Normal male seen from left side, X 236 ; x. conical eminence on the dorsal side of the head. 



2 g. Frontal thread of one of the minute males, X 260. 



2 h. Larva seen from below, X 264. The natatory legs are omitted. 



2 i. Hinged larva seen from above, X 125. 



3. Aspidoecia Normani Giard and Bonnier. 1 ) 



3 a. Male of Erythrops abyssorum G. 0. Sars seen from above and infested with nine female parasites 



of very different size and one larva, X lz h; a. larger female, b. smaller females, I. larva, 

 in. male. The posterior part of the abdomen of the host is omitted. 



3 b. Female with two rudimentary ovisacs (w.) and three larvae (v.) attached to the dorsal surface 

 of the second abdominal segment of Erythrops serratus G. 0. Sars, X 24 ; r'. chitinous knots 

 where the entrances to the receptaculum seminis must be found. 



3 c. Sub-adult female attached to the back of the first abdominal segment of an Er. serratus and 

 seen from the dorsal side, X 39; x. two males hinged by their frontal thread, y. part of the 

 skin of the host. 



3 d. Head of a female from Er. serratus, seen much from in front, X 350; d. mouth, e. maxillula, 

 s. adhesive plate, t. internal space possessing a peculiar refraction of light. 



3 e. External genital organs and receptaculum seminis of the female whose head is shown in fig. 3 d, 

 X 70; e. solid ring, g. genital aperture, k. hole in the ring, o. chitinous knots, r. receptaculum 

 seminis with its ducts. 



3 f. Adult female from Er. abyssorum, X 24; the head is seen in the middle. 



3 g. The same male seen from the side opposite of that of fig. 3 f ; r. ring around a genital aper- 

 ture, r'. chitinous knots. 



3 h. Head of the female shown in the two preceding figures, cleaned with caustic potash and seen 

 from below, X 350; a. antennula. 



3 i. Genital aperture and its surroundings of the female shown in fig. 3 f, X 170; e. ring-shaped 

 skeleton, f. less solidly chitinised part of the ring, g. genital aperture with its lips, k. hole 

 in the ring, m. muscles. 



3 k. Male from Er. serratus seen from below, X 291 ; b. olfactory seta of the antennula, q. sper- 

 matotheca. (In other specimens two spermatothecaj were found.) 



3 1. Another male from Er. serratus seen from left side, X 324. 



*) On the plate is written Normanni instead of Normani. 



26* 



