171 
(Kr.). Hitherto found only in the Kara Sea, the Murman Sea, near Tromsé (Norway) and 
off the West-coast of Greenland, and the genus has been found only on Hipp. Gaimardii 
M.-Edw. and Hipp. polaris (Sab.). 
REMARKS. The genus contains only two species. As, in spite of the most careful 
investigation, the male has not been found, our knowledge is defective in an important point. 
Judging from the structure of the female, the ovisacs, the larva and the pupa, the genus 
comes very near to Spheronella, and the only really good character appears to me to be 
the rudimentary maxillipeds of the female. A biologically important character is that — as 
stated above — it lives in the branchial cavity of Decapoda Caridea, as the genus Homoeo- 
scelis lives in the branchial cavity of Cumacea. 
Conspectus of the Females. 
The frame of the head is an almost regularly transverse oval and provided exteriorly on 
each side with a very long list which proceeds from the centre of the lateral outline and runs 
outward, and especially backward, in an oblique direction. .... . 1. Ch. mirabile H. J. H. 
In the frame of the head the foremost lateral angle is strongly produced, forming a 
good-sized, fairly broad and not quite short projection, a large part of which is covered by 
the skin, whereas the very long lateral, essentially backward running list mentioned in the 
preceding species is wanting... . 2. Ch. Hansenii Giard and Bonnier (without description). 
|. Choniostoma mirabile H. J. H. 
(PI. X, fig. 5a—5e; pl. XI, fig. 1a—1k.) 
Choniostoma mirabile H, J. Hansen, Dijmphna-Togtets zool.-bot. Udbytte, 1887+), p.271—78, Tab. XXIV, 
fig. 7—7h. 
— — Guard and Bonnier, Bull. scient. de la France et de la Belgique, T. XX, 1889, p.346, etc. 
— —  Giard and Bonnier, Bull. scient. de laFr. et d. |. Belg. T. XXV, 1895, p. 479. 
FEMALE. The specimen represented in fig. 5a is 35 mm. in length, 4 mm. in 
breadth; its shape is described in the diagnosis of the genus. The smallest specimen found 
is a young one, 1°35 mm. long and 1-28 mm. broad, thus a little longer than broad, almost 
circular in appearance, and somewhat flattened like the adult. The area surrounded by the 
frame of the head (fig. 1a) is regularly rounded, somewhat shorter than broad; the anterior 
part of the frame is fairly narrow between the antennule, scarcely rising above the surrown- 
ding soft membrane and exhibiting outwardly only a very narrow list, while its broader 
part (indicated by a dotted line) is covered by the skin. The lateral and posterior parts of 

1) Separate copies of my contribution were distributed in the beginning of July 1886, whereas the whole 
volume with the résumé appeared in 1887. 
22* 
