ALCIPPE LAMPAS. 537 



the exterior transverse muscles, which are situated more 

 towards the carinal portion of the peduncle and capitulum, 

 and which are common to most Lepadidae. The internal 

 transverse muscles, and those running to the lower end of 

 the orifice, are peculiar, but we shall hereafter meet with 

 them even more developed in Cryptophialus. 



Along the medial carinal line there is, between the two 

 layers of corium, the usual circulatory channel. On each 

 side of this line, on the inside of the sack, there are gene- 

 rally some slight irregular swellings, and sometimes a large 

 extent of the inner surface is irregularly carunculated with 

 little knobs. The sack (e in fig. 5) extends down almost to 

 the basal point of the peduncle (d), more especially when 

 the ovarian caeca are not gorged with ova. 



Brancliice, or ovigerous Frcena. — Within the sack, on 

 each side of the body, rising not far from the ends of the 

 adductor muscle (6), there is a large fillet or fold ; the two 

 occupy so exactly the position of the ovigerous fraena that 

 I cannot doubt such is their nature, though, as happens in 

 the case of some species of Pollicipes, they are destitute of 

 their proper glands, and so do not serve for the attachment 

 of the ovigerous lamellae ; this attachment probably is not 

 required, owing to the protected situation which the lamellae 

 hold in the sack, under the animal's body, and over the 

 ovarian caeca. From the unusually large size of these so- 

 called fraena, I cannot doubt that they serve as branchiae, 

 equally well with the plicated folds of membrane, believed 

 to be homologous with the fraena, in the Balaniclae, which 

 have by every one been considered as branchiae. The fraena 

 are broad and truncated at their upper ends ; their margins 

 are sinuous, and their outer surfaces papillose; they run 

 longitudinally down the sack, narrowing as they extend, 

 almost to the basal point of the peduncle, and hence are of 

 considerable length ; they are hidden in the section (fig. 5) 

 by the medial, somewhat protuberant mass (c) of ovarian 

 caeca, and partly by the (i) prosoma. 



Body. — The body is constructed on the usual type, and 

 indeed does not differ greatly from that of Ibla. The 

 labrum is very large, its lower or basal margin is separated 

 by an unusual space (capable of being contracted or folded) 



