232 



BULLETIN 93_, UNITED STATES NATIONAL MUSEUM. 



Specimens from Bermuda which I have seen agree with Darwin's 

 description. The irregular, strongly marked ridges of growth on 

 the lower part of the rostrum show that individuals 8 to 9 mm. long 

 are old. The maximum length of rostrum given by Darwin is .3 

 of an inch, or about 7.5 mm. 



Professor Verrill's var. cuspidatus, from Bermuda, is described as 

 follows : 



Our specimens differ as a variety from tlie typical form described by Darwin, 

 in having the summit of the rostrum divided into four or six acute denticles ; 



Fig. 74. — Balanus declivis. a, cierus iv, the spines omitted, b, lowee part of the 



SAME. C, riFTH SEGMENT, AND d, TENTH SEGMENT OF CIRRUS IV. €, 22D SEGMENT OP 

 CIKRDS VI. 



it is very convex and considerably incurved. The summit of the carina is 

 bilobed by a narrow incision. The base is membranous and very obliquely 

 placed, owing to the downward prolongation of the rostrum, as in the type. 

 Long Bird Island, on the flats, embedded in a blackish massive keratose sponge 

 (Spongia, sp.), which often lives half buried in the calcareous sand at low tide, 

 and which also harbors a small Alpheus and several isopod crustaceans. 



The denticles at the summit can only be produced by breakage or 

 erosion, and their presence in Professor Verrill's specimens is prob- 

 ably accidental — an individual and not a racial character. Some 

 specimens I have seen show faint gray and white longitudinal stripes 

 near the summit of the rostrum, possibly indicating differences in the 



