CRUSTACEA MALACOSTRACA. III. 



I 9 I 



133. Synidothea nodulosa Kroyer. 



! 1846. Idothea nodulosa Kroyer, Naturh. Tidsskr. Ny Rsekke, Vol. II, p. 100. 



? — Kroyer, in Gaimard, Voy. en Scand., Crust PL 26, figs. 2 a — 2 v. 



! 1880. Synidothea nodulosa Harger, Rep. U. S. Comm. Fish and Fisheries, Pt. VI, p. 351 ; PL VI, figs. 



33—35- 

 1905. — — Richardson, Monograph, p. 388, figs. 429 — 430. 



In the marsupium has been found the Epicarid Clypconiscus Meinerti Giard & Bonn., to be 

 dealt with later on. 



Occurrence. This fine form has not been taken by the "Ingolf". 



It has been captured three times at West Greenland, viz., at Godhavn, Lat. 69°i4' N., 8 — 10 

 fath., sand; at Lat. 66°46' N., Long. 54°io' W., 18 fath., stones with many Balani (H. J. Hansen), finally 

 at "Southern Greenland", 12 — 15 fath., sand (Kroyer). 



Distribution. West Spitzbergen, 61 fath. (G. O. Sars) and 48 fath. (Ohlin); some places on 

 the west coast of Novaya Zemlya, from 3—6 to 5 — 20 fath. (Stuxberg) ; in Jugor Schar, 6 fath., and 

 5—8 fath. (Hansen, Stuxberg), and some places in the Kara Sea, 8 to n fath. (Stuxberg). Ohlin says 

 that it occurs in the sea north of Siberia, but I cannot find any positive locality recorded in the lite- 

 rature. It is unknown from Ellesmere Land and the west coast of Baffin Bay and Davis Strait, but 

 has been taken more southwards at Nova Scotia and George Banks, in 16, 18 and 190 fath. (Harger). 

 Filially it has been recorded from a place north of Queen Charlotte Island, British Columbia, 111 fath. 

 (S. I. Smith; Harger). 



S. nodulosa^ which generally occurs in rather low water, has by Ohlin been considered as cir- 

 cumpolar. It may be so, but it is still extremely uncertain, as the statements above show that our 

 knowledge is still very imperfect. 



Family Arcturidse. 



The material comprises three genera: Arcturus Latr., Pleuroprion zur Strassen, and Astacilla 

 Cordiner. In these genera and probably in the whole family the first thoracic segment is immovably 

 coalesced with the head. — The maxillipeds of females with marsupium have their basal part altered 

 and expanded for producing a current of water; the structure of the maxillipeds in the male and the 

 adult female of Astacilla granulata G. O. S. has been described above on p. 185. 



The number of marsupial plates has been used as generic characters by recent writers, but in 

 most cases the number stated by them is quite wrong. G. O. Sars said in the "Account" p. 88, that 

 Arcturus (most probably he had examined A. Ba/Jini) has three pairs of marsupial lamellse "issuing 

 from the 2nd, 3rd and 4th segments", while Astacilla has only "a single pair" of lamellse, on fourth 

 segment. Richardson gives the same numbers in the Monograph. Before quoting further statements 

 on Astacilla and closely allied genera it may be said, that in Arcturus Baffini I find five pairs of 

 lamellae belonging to the five anterior pairs of thoracic legs; first pair are considerably smaller than 



