126 CRUSTACEA MALACOSTRACA. III. 



Length of the largest specimen, a female without marsupium, 3^8 mm., of a male 3 mm. 



Remarks. It is after prolonged hesitation that I establish this species on the rather small 

 specimens to hand. I was inclined to think that they were only less than half-grown specimens of /. 

 hirticeps with the spines on the head and the spines or crenulation on the anterior thoracic segments 

 still undeveloped. But the smooth and narrow head seems most probably to be a specific character, 

 as most of my young specimens of /. hirticeps of the same size, or even a little smaller, have the head 

 broad as in the adults, and in small specimens of /. hirticeps measuring 2-33 mm - from Stat. 138, 

 and with the head nearly as narrow as in /. dubia, both the head itself and the thoracic segments have 

 long spines. Furthermore, the fact that the male has the flagellum multiarticulate with well developed 

 sensory filaments, seems to indicate that, though only 3 mm. long, it cannot be far from adult. But 

 being, nevertheless, not quite sure, I choose to name the form /. dubia and must let the future decide 

 its value. 



Occurrence. Taken by the "Ingolf" at two stations in the cold area. 



North-East of Iceland: Stat. 120: Lat 6f2<j N., Long. u32' W., 885 fath., temp, -f- ro; i spec. (.) 



Stat. 119: Lat 6753' N., Long. ioi9' W., 1010 fath., temp. -^- 1-0; 2 spec. 



(<? and ?). 



81. Ilyarachna Bergendali Ohlin. 



1901. Ilyarachna Bergendali Ohlin, Bihang till K. Sv. Vet Akad. Handl. Vol. 26, IV, No. 12, p. 37, figs. 



8 a 8d. 



Of this species I have not seen any specimen. It has been established on three specimens, 

 and wishing to examine some features I wrote to the Director of the department in question of the 

 Riksmuseum in Stockholm, Dr. Hj. Theel, but he answered that the specimens could not be found, 

 and after the death of Ohlin they were probably lost in one way or another. Consequently I can only 

 make some remarks based on Ohlin's description and figures. 



7. Bergendali is certainly a valid and even an interesting species, as the antennae are much 

 longer than in any other form from the North Atlantic; the penultimate joint of the peduncle is, ac- 

 cording to Ohlin's fig 8 a, even a good deal longer than the whole body, and nearly half as long again 

 as the following joint; if these joints are lost the species can be separated by having the proximal 

 four-jointed part of the antennae considerably larger than in the other forms of this genus. According 

 to Ohlin's fig. 8c the basal joint of the antennula has a somewhat aberrant shape; his fig. 8d, repres- 

 enting the fifth thoracic leg, shows that the third joint is considerably thicker, the fifth joint narrower 

 in proportion to length, and the seventh joint longer in proportion to the sixth than in /. hirticeps. 

 The anterior margins of the four anterior segments are said to be crenulate, and the fifth segment 

 "not at all emarginated behind", but the latter statement is somewhat astonishing. 



Ohlin wrote: "Oral parts in no respect differing from those in /. hirticeps^ but unfortunately 

 he did not say plainly whether a mandibular palp was found or not. His text contains nothing on the 

 uropods, and I am not sure that they do not possess an exopod. For these and other reasons /. Ber- 

 gnidali is mentioned later on in the remarks on Echinozone arctica. 



