658 



having below a small dentiform projection, defining angle rather projecting, 

 being tipped by a strong spine, and having at the base another spine issuing 

 from a small tuberculiform projection, dactylus rather strong and evenly curved; 

 posterior gnathopoda in male very much elongated, and attached far behind 

 the middle of the corresponding segment, basal joint long and slender, pro- 

 podos oblong in form, being 3 times as long as it is broad, palm irregularly 

 indented, having, at about the middle, an acute projection, and in front, a rather 

 projecting, angular lobe, the two being separated by a deep sinus, defining angle 

 as in the female; dactylus very strong and abruptly curved in its outer 

 part, inner edge somewhat flexuous and densely setous. Branchial lamellae 

 of moderate size and oval in form. The 3 pairs of pereiopoda rather strongly 

 built, with the propodal joint twice as long as the carpal one, palm occupy- 

 ing 2 /s of the length of the joint, and defined by a slight angle carrying 2 

 juxtaposed spines. Body of a more or less deep claret colour. Length of 

 adult female reaching 9 mm., of male 15 mm. 



Remarks. The very pronounced sexual difference in this form has 

 caused the establishment of several spurious species. Thus the Caprella lobata 

 of Sp. Bate is undoubtedly the adult male of his C. linearis, and Rathke 

 even described the species under 3 different names, as C. phasma, acuminifera, 

 and scolopendroides. As in some other species of the genus, the young, not 

 yet sexually developed male does not much differ from the female, whereas 

 the adult male acquires a very different appearance, both in the great pro- 

 longation of the 2 anterior body-segments, and in the structure of the 

 posterior gnathopoda, partly also in that of the superior antennae. The lat- 

 ter organs, moreover, seem to be .subjected to some variation as to the form of 

 the peduncular joints and the relative length of the flagellum, which led Boeck 

 to the establishment of another spurious species, C. laticornis. The size is 

 also very variable, and the male is always much larger than the female. In 

 the male sex this species may be easily recognized by the structure of the 

 posterior gnathopoda, the basal joint of which is unusually long and slender, 

 the propodos being also very much elongated and narrow in proportion to 

 its length. 



Occurrence. The species is very abundantly met with along the 

 whole Norwegian coast, from the Christianiafjord to the North Cape in com- 

 paratively shallow water among algss. 



I attribution. British Isles (Sp. Bate), Bohuslan (Bruzelius), Kattegat 

 (Meinert), the Baltic (Moebius), Dutch coast (Hoeck), coast of France (Chevreux), 

 Iceland (Norw. North Atl. Exped.). 



