. Bulletin - United States National Museum. Science. 156 BULLETIN 9.'!, UNITED STATES NATIONAL MUSEUM. of the antei-ior ramus, as far as the twelfth segment. On the pos- terior ramus there are fewer spinules, and fewer segments. On the fourth cirrus there are a few spinules, chiefly of the flat multifid form, in a row near the distal sutures of the segments. There. Fig. -BALANUS EALANUS from ABERDARE CnAXXEL. THREE INDIVIDUALS. X a, SCDTUM AND b, C, (I, TERGA OF are many erect, mainly simple spinules on the second segment of the pedicel. Cirrus iv has minute, flat multifid spinules on the
. Bulletin - United States National Museum. Science. 156 BULLETIN 9.'!, UNITED STATES NATIONAL MUSEUM. of the antei-ior ramus, as far as the twelfth segment. On the pos- terior ramus there are fewer spinules, and fewer segments. On the fourth cirrus there are a few spinules, chiefly of the flat multifid form, in a row near the distal sutures of the segments. There. Fig. -BALANUS EALANUS from ABERDARE CnAXXEL. THREE INDIVIDUALS. X a, SCDTUM AND b, C, (I, TERGA OF are many erect, mainly simple spinules on the second segment of the pedicel. Cirrus iv has minute, flat multifid spinules on the distal parts of the segments of both rami. In cirrus vi the segments of the pedicel have many minute, multifid spinules, but there are none on the segments of the rami. These have 40 segments, bear- ing six pairs of sphies. The fourth and part of the segments of the fifth cirri have five pairs of spines. The penis is typical except that I can find no trace of the point near the hase^ char- acteristic of B. halanus. The individual dissected is certainly adult, the largest of a consider- able series (fig. 45). The habit of this colony is to grow in branching groups, un- like the usual colonies of B. halanus. Greenland (Upernavik) speci- mens attain a good size, 44 mm. in diameter and height. Ribs as in typical B. halanus but weaker, often hardly noticeable. Tubes of the parietes large. Beak of the tergum white. Darwin also has noted that in Arctic specimens the terga have white beaks. Labrador specimens from GO fathoms are deficient in ribs, with the aperture as large as the base. The terga and sometimes the. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original United States National Museum; Smithsonian Institution; United States. Dept. of the Interior. Washington : Smithsonian Institution Press, [etc. ]; for sale
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