

Uppei' line 

 straight. 



Upper line 

 convex. 



8 teeth .... 



7 „ 



6 „ .... 

 5 „ 



1 specimen 



7 „ 

 21 „ 



8 „ 



1 specimeu 



„ 



2 „ 



1 •, 



190].] CBUSTACEA Oi? THB " SKEAT EXPEDITION." 669 



relative proportions of the joints of the 2nd pair are notably 

 different. 



The rostrum, then, is short and just reaches to the ends of the 

 antenual scales, or even falls a Httle short of them. 



On its under edge it bears 3-4 teeth ; on its upper edge from 

 5-8 teet!), not including a very small tooth, which gives to the tip 

 a bifid appearance. In most cases the upper line of these teeth 

 is straight, but in a few cases it is markedly convex, owing to the 

 teeth that lie over the eyes (teetli 2-4) being raised above the level 

 of those before and behind them ; aud in yet other cases the upper 

 line is curved, but not nearly so markedly. I summarize these 

 characters in 50 individuals : — 



Upper line very 

 moderately convex. 



specimen 



4 „ 



5 „ 



„ 



Thus it appears that out of 50 individuals, 28 have 6 

 teeth, 11 have 7 teeth, 9 have 5 teeth, and 2 have 8 teeth ; so 

 that 6 teeth may be considered the normal number for the species, 

 but a number tending to vary on either side of the norm ; and 

 similarly with the straightness of the upper line of the teeth, this 

 character, however, varying only on one side of the norm. The 

 outer raaxillipedes reach beyond the antennal peduncles by the 

 last joint or nearly the last joint ; the 1st pair of legs reach 

 beyond the scaphocerites (?'. e. beyond the anterior angle of their 

 outer border) by the last joint, the 2nd pair by the last joirrt aud 

 nearly half the carpus. The carpus of the 2nd pair is thickened 

 at its distal articulation, aiid the proportions of the different 

 joints are as follows (in an individual 40 mm. long) :— 



Eight leg . . . 

 Left leg ... 



The greater length of the carpus of the left side in this 

 specimen is, however, abnormal ; in other specimens the pro- 

 ])ortions are the same on both sides. The last three legs increase 

 in length from before backwards, the 4th pair reaching beyond the 

 3rd pair quite by the last joint, and the 5th pair reaching beyond 

 the 4th pair barely by the last joint; the 5th pair, moreover, 

 exceed the scaphocerites by the last joint and a third of the 

 penultimate joint. All the legs are slender and quite smooth ; the 

 fingers of the 2nd pair are unarmed. 



The internal antenna; are a little longer than the animal itself 

 (47 mm.) and about half the length of the external antenna;. 

 The telson ends in a sharp point, which is much shorter than the 

 internal of the two lateral teeth, the external of which is very 

 small. 



Merus. 



Carpus. 



Palm. 



Fingers. 



5 mm. 



7 mm. 



3-25 mm. ' 



2"25 mm. 



5 „ 



8 „ 



3-25 „ 



2-25 „ 



