530 LEPADID^E. 



is of course the usual double fold of corium, these two 

 folds being united by minute, transverse, ligamentous 

 fibres, branched at the two ends, as in other Lepadidse. 

 Imbedded in the corium there are numerous, longitudinal, 

 striae-less muscles, which do not run quite up to the orifice, 

 but to an oblique line beneath it. Externally to these 

 muscles there are, as in the other Lepadidae, fine trans- 

 verse muscles, confined to the middle part of the animal, and 

 running from the carinal margin more than half way round 

 both sides. Attached to the upper notched or folded end of 

 the orifice (y, fig. 5, above the upper ends of the longitudinal 

 muscles), there is a fan of rather strong, striae-less muscles, 

 expanding downwards, with their lower extremities attached 

 to the outer membrane of the capitulum ; these muscles 

 apparently serve to open the orifice : there is a somewhat 

 analogous muscle in Lithotrva, but in no other member of 

 the Family : in Cryptophialus, however, there is a closely 

 similar muscle. Owing to the action of these several 

 muscles, the tissues forming the capitulum and peduncle 

 are, according to Mr. Hancock, highly contractile. 



I have stated that the under surface of the upper pro- 

 duced end of the horny disc is concave, and serves for the 

 attachment of several muscles. Of these some run to the 

 basal margin of the great labrum, and no doubt, as usual, 

 move the whole mouth ; others, as usual, run to the skin 

 between the labrum and the lower end of the orifice, — 

 /. e. in fig. 5, between the lower end of the row of fine 

 hairs (see fig. 11), which shows where the basal margin 

 of the labrum is situated, and the lower side of the point 

 (a), where the orifice terminates : others run obliquely 

 on both sides towards the point of attachment of the small 

 adductor scutorum muscle {b, fig. 5) : others, of considerable 

 strength, and these are more peculiar, run and are attached 

 to the lower end of the orifice (a), and serve apparently 

 to draw up the orifice from within the fissure-like cavity, 

 in which it lies lodged : others, again, extend transversely 

 on both sides, close beneath the inner tunic of the sack, 

 a little bevond the line whence the ovi°:erous frama or 

 branchiae arise. These transverse muscles lie within the 

 longitudinal muscles, and therefore are quite different from 



