THE SESSILE BARNACLES. 45 



VERRUCA DARWIN! Pilsbry. 



1907. Verruca darwini PILSBRY, U. S. Nat. Mus. Bull., No. 60, p. Ill, pi. 10, 

 figs. 4-8. 



Type. Cat. No. 9015, U.S.N.M. 



Type-locality. Albatross station 2042, east from New Jersey, 

 north latitude 39 33', west longitude 68 26' 45" in 1,555 fathoms, 

 bottom temperature 38.5 F. Also at Albatross station 2573 south- 

 east of Cape Cod, north latitude 40 34' 18", west longitude 66 09', 

 in 1,742 fathoms, bottom temperature 37.3 F 



This species was described from two examples from the type- 

 locality. Another specimen (Cat. No. 32923, U.S.N.M.) has now 

 turned up from Albatross station 2573. It agrees substantially with 

 the type in contour, but has a pair of ribs on the movable scutum 

 like the individual drawn in plate 10, figure 8, of my former paper. 

 This is probably the usual condition. This example from station 

 2573 measures: Carinorostral length of base 6 mm.; between apices 

 6.2 mm.; diameter of base 3 mm.; height of fixed terguin from apex 

 to base 4 mm. 



Cirrus i has subequal rami of about 8 segments. Cirrus ii has the 

 wide, obtuse, anterior branch two-thirds the length of posterior, 

 both being densely bristly. Cirri iii and iv are nearly similar, com- 

 posed of segments armed with two pairs of spines on the anterior 

 side (or in a few segments three pairs). Cirrus v has only one pair 

 of bristles on the anterior side of most of the segments. In cirrus vi 

 there are mostly three pairs of bristles, as usual in the genus. The 

 terminal appendage is longer than the protopod of cirrus vi, com- 

 posed of 11 segments copiously bristly at their distal ends. The 

 penis is 2.8 mm. long, nearly twice the length of protopod. It has 

 a few short hairs near the end, as in all other Verruca. 



Verruca darwini is closely related to V. ratlibuniana, from which 

 it differs by the less regular sculpture, especially of the parietal areas 

 of the plates of the wall; by the much lower contour, and finally the 

 less erect movable plates, which in slope form a smaller angle with 

 the plane of the base. 



There is a further difference in the basal margin of the wall, which 

 is beveled to a simple sharp edge in V. darwini, while in V. ratli- 

 luniana and V. bicornuta there is a sort of inflexed border or hem 

 within the edge. This may, however, be a difference due to age. 

 The reduction in the number of spines on several cirri is notable, 

 because very unusual in this genus. 



The cream-white tint and comparative sizes of the plates and the 

 absence of any myophore or pit in the fixed scutum for the scutal 

 adductor muscle are characters in common with V. rathbuniana, V. 

 bicomuta, and various other deep-water species. 



