198 



BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 



The form Icevidomus often has a strong superficial resemblance 

 to Balanus wneas Lanchester, 1 from the Malay Peninsula, but the 

 following differences may be noted : In B. hesperius the spur of the 

 tergum is wider and very much closer to the basiscutal angle. The 

 articular and adductor ridges of the scutum are shorter and differ in 

 shape. Finally the radii are much better developed. 



Somewhat doubtful records are Albatross stations 2869, 2872, 

 3508, and 3282. These may be the young of either hesperius or Icevi- 

 domus. 



Ribbed forms of B. hesperius, from the Asiatic coast. A series 

 from Albatross station 3780, attached to egg-capsules of Chrysodo- 

 mus, taken off Kamchatka in 12 fathoms, is externally of the typical 

 ribbed form; basal diameter 9 to 11 mm. (pi. 49, figs. 7-7&). The 

 scuta differ by having growth-ridges decidedly more widely spaced, 

 as in Puget Sound hesperius. In most individuals the valve has the 

 shape of a right-angled triangle with basal and tergal margins sub- 

 equal ; but sometimes the angle is slightly greater, and the tergal mar- 

 gin longer. The spur of the tergum is longer than usual. 



A similar form was taken at Albatross Station 5003, off southwest- 

 ern Saghalin Island, growing on a Turritella, in 35 fathoms, bottom 

 temperature 42.4 F. In this lot the labrum (fig. 62<?) has three 

 teeth on one side of the median cleft, one on the other. The palpi 

 differ from those of t^ypical B. hesperius. The longitudinal row of 

 bristles on the labral side (fig. 62c) is short, with similar pectinated 

 bristles scattered above it. The patch of bristles near its distal end 

 is situated near the upper margin. All of these spines are pectinated. 

 There is no distal patch of long spines on this side of the palpus. 

 The outer side of the palpus has a very dense distal patch of long, 

 simple bristles (fig. 62c?). 



The mandible does not differ materially from that figured for 

 hesperius. Maxilla (fig. 62e) is notched under the upper pair of 

 great spines, a pair of short spines in the notch. There are five 



1 On the Crustacea collected during the Skeat expedition to the Malay Peninsula, 

 Proc. Zool. Soc., London, 1902, vol. 2, p. 370, pi. 34, figs. 4, 4o. 



