ON A LARGE PENELLA-SPECIES. 231 



mm. in length, that were deeply fixed within the blubber 

 of the animal '). 



The head is swollen, globous, nearly twice as broad 

 as the neck; its frontal side is faintly concave, with 

 a shallow longitudinal groove in the middle and is 

 furnished with the well-known branched protuberances, 

 that are however much less developed as in other species 

 f. i. in P. sagitta, varians and exocoeti, where they are 

 projecting a good deal beyond the surface of the head. 

 Two long and slender arm-like processes are emerging 

 from the posterior end of the head, with a very acute 

 angle ; they are half as thick as the neck and have a 

 length of 18 mm., measuring therefore nearly a tenth of 

 the total length of the animal. In most Fenellas]^ec\es the 

 arm-like processes are short and obtuse, projecting from 

 the body nearly with a right angle, in the small P. sa- 

 gitta however they are very long, directed posteriorly and 

 reaching a third of the total length of the body. In none 

 of our specimens I could detect a trace of a third arm- 

 like process, like it occurs in P. varians and P. crassi- 

 cornis; P. histiophori also appears to possess a third rudi- 

 mentary arm, for Thomson says: » between them (the arras) 

 and projecting a little posteriorly is a rounded protube- 

 rance", though he failed to mention if it is placed dor- 

 sally or ventrally. However there cannot be looked on the 

 presence or absence of this third process as a character 

 of much importance, since Steenstrup and Lütken, examin- 

 ing nine adult specimens of P. varians, stated that in four 

 of them three arm-like processes occurred, whereas in the 

 five others there were only two. 



Upon the dorsal side of the head, not far from the 

 frontal margin, two pairs of antennae are situated. The 

 anterior of them (fig. 2) are two-jointed, consisting of a 

 short apical joint and a long basal one, though I believe, 

 that in the middle of the last one also an articulation is 



1) loc cit. p 198. 



Notes from the Leycien IMuseuiu, 'Vol. XXVI. 



