REPORT ON THE CIRREPEDIA. 75 



unequal rami ; tke most anterior one is shorter and a great deal thicker than the posterior 

 one. The former has five, the latter six segments. 



This species was taken at Station 49, May 20, 1873 ; lat. 43° 3' N., long. 63° 39' W. ; 

 depth, 83 fathoms; bottom temperature. 1°*8 C. ; bottom, gravel, stones. Numerous 

 specimens. Station 10, cruise of II.M.S. "Triton;" August 24, 1882; lat, 59° 40' N., 

 long. 7° 21' W. ; depth, 51G fathoms. Bottom, mud; bottom temperature, 8' C. Two 

 specimens. 



Observations. — This species seems to be common throughout the northern part of the 

 Atlantic Ocean. A very interesting observation was made in one of the specimens 

 dredged in August 1882 by H.M.S. "Triton." On opening it, I found it contained eggs. 

 They were large and not extremely numerous. On studying them with the microscope I 

 found they had passed already the Nauplius-stage, and had arrived at the Cypris-s1 

 The exuviae of the Nauplius-larva still adhered to the covering of the Cypris, though it 

 was not easy to make out which parts had developed from the Nauplius-appendages. I 

 figure an egg in the Cypris-stage in fig. 1 of PI. VIII. The first pair of Nauplius- 

 appendages changed into the antennas of the Cypris, but of the two other pairs only one 

 was visible. Whether its basal part has changed into one of the excrescences which fill 

 up the interspace between the antennae and the cirri, I cannot say with certainty. Of the 

 cirri there are six pairs, behind which a rudimentary cirrus is still observed. They almost 

 seem to have developed within that part of the Nauplius-larva which, as a distinct 

 excrescence, is attached to the ventral side. 



When complemental males are present there is one attached to the interior side of the 

 scutum. PI. VIII. fig. 4 shows the place it occupies (a). The chitinous membrane 

 covering the valve on its interior surface forms a little pouch, the opening of which is 

 directed towards the occludent margin of the valve. In this pouch the male is lodged. 

 I got two rather different specimens of this male, and as I think our knowledge is still 

 very insufficient in this respect, I give figures of both specimens. Probably the male 

 figured in fig. 2 (PI. VIII.) has not yet quite passed through its metamorphosis. At 

 the one extremity it is furnished with the two small prehensile antenna' (an.), and at the 

 other extremity a kind of disc is observed with an opening in it. The body is very flat. 

 Muscles are seen running towards the antenna?, and probably the testis and the genital 

 duct are represented. In the other stage (fig. 3) the animal has grown more robust : the 

 body is no longer flat, but the size has slightly diminished: in the stage of fig. 2 the size 

 is 0'8 mm., in that of fig. 3 only 0'6 mm. The disc-like appendage has disappeared, and 

 the two prehensile antenna' are now represented by a single stout excrescence. As 

 in the first stage, the chitinous membrane which covers the body is rather thick : it is, 

 however, no longer so distinctly striated as was the case in the first stage. The internal 

 viscera are much better to be distinguished; they are only represented by the genital 

 apparatus. This consists of a glandular mass, the testis (t.) and a duct, which is much 



