254 SCALPELLUM RUTILUM, 



Mandibles with three teeth : maxilla? narrow, bearing 

 only four or five pair of spines : segments of the second 

 and third pair of cirri with one side wholly covered with 

 spines. 



Males, two, lodged in hollows, on the under sides of 

 the scuta ; pouch-formed, with four (?) rudimentary valves ; 

 no mouth; cirri not prehensile. 



Hab. unknown; associated with Dichelaspis orthogonia. British Museum. 

 FEMALE OR HERMAPHRODITE. 



There is only a single specimen in the British 

 Museum, and this had nearly all its valves separated, 

 and many of them in fragments : from its state of decay, 

 I think the specimen must have been dead, when origi- 

 nally collected. 



Description. — The capitulum consists of fourteen valves, 

 including from analogy a rostrum.* Valves, apparently 

 covered with membrane, bearing some thin spines on the 

 margins; clouded with a fine, though pale, orange tint ; 

 surfaces plainly marked with lines of growth. 



Scuta, elongated, nearly three times as long as broad; 

 apex, pointed ; basal margin extremely oblique, forming 

 an acute angle with the occludent margin ; the lateral 

 margin is slightly hollowed out, and is separated from the 

 tergal margin by a large rectangular projection or shoulder. 

 The occludent margin is nearly straight ; externally, there 

 is a slight ridge running down the middle of the valve, 

 from the apex to the baso-lateral angle ; and a second 



* In my first, and as I thought careful examination of the separated 

 valves (my only materials) of this species, I mistook one of the triangular 

 rostral latera for the rostrum, and hence was unfortunately led into an 

 error in my c Monograph on the Fossil Lepadidae of Great Britain,' in which 

 I state that the present species has only twelve valves in the capitulum ; 

 and I inferred from this, that S. quadratum, S.fossula, &c, had only twelve 

 valves ; I still believe this to be correct, but the existence of fourteen valves 

 in S. rutilum and S. ornatum, the recent species to which the above fossils 

 are most closely allied, no doubt is a strong argument in favour of this 

 higher number. 



