206 IBLA QUADRIVALVIS, 



Colour. — From some well-preserved dryed specimens 

 in Mr. Stutchbury's possession, it appears that the sack, 

 cirri and tropin, were dark blue, as in I. Cumingii; after 

 being long kept in spirits, these parts become brown. 



Generative System. — The penis (PL IV, fig. da) is very 

 singular in structure ; it is of the ordinary length, but 

 of small diameter ; it tapers but little ; it consists of a 

 moveable articulated, and a fixed unarticulated portion ; 

 this latter is smooth, much flattened, not divided into 

 segments, and projects straight out under the caudal 

 appendages ; it is about one third of the length of the 

 entire penis ; it corresponds with a part present in all 

 Cirripedes, but here surprisingly elongated. The articu- 

 lated portion consists of separate segments, twenty in 

 number, quite as distinct as those of the cirri ; each one 

 is oblong, being longer by about a third part than broad ; 

 each has a few short bristles round its upper margin ; 

 the terminal segment has a circular brush of bristles. 

 The vesiculae seminales are easily seen, though they are 

 narrow ; they are slightly tortuous ; they enter the pro- 

 soma, and lie on each side of the stomach ; their outer case 

 has a ringed structure, but is not fibrous ; the contents 

 in the best specimen consisted of a mass of spermatozoa, 

 which I saw with perfect distinctness. The testes are 

 unusually large and egg-shaped. 



Ova, spherical, ^ths of an inch in diameter, united as 

 usual into two ovigerous lamellae. The ovigerous fraena 

 are extraordinarily small, and might be very easily over- 

 looked ; their length, in a full-sized specimen, was only 

 5^ths of an inch, and they projected only ^ths from the 

 inner surface of the sack. The glands on their margin, 

 to which the lamellae adhere, are pointed oval, with 

 an extremely short footstalk, and that rather thick ; the 

 entire length of gland and footstalk, being only ^ths of 

 an inch. The larvae, in their first stage of development, 

 offer the usual characters, and closely resemble those of 

 Scalpellum ; the probosciformed mouth, however, is re- 

 markably prominent, and the limbs unusually thick. 



