248 SCALPELLUM ORNATUM, 



peduncle, in the scuta not being added to at their upper 

 ends, and in the membrane covering and connecting the 

 valves being spineless ; but there is a greater difference in 

 the trophi and in the cirri. The peduncle of S. ornatum 

 presents some resemblance to that of the singular creta- 

 ceous genus, Loricula. 



MALE. 



All the specimens, as already stated, were dry, but in 

 an excellent state of preservation, so that after having 

 been soaked in spirits, they could be minutely examined. 

 In the four which I opened, I found, in a transverse pouch 

 on the under side of each scutum, a male lodged ; in a 

 fifth dead and bleached specimen, the cavities in the shell 

 for the reception of the males, were present; and in a 

 sixth young specimen, also dead, cavities were in process 

 of formation. As compared with plants, the relation of 

 the sexes in this species may be briefly given, by saying 

 that it belongs to the class Diandria monogynia. I will 

 first describe the males themselves, and then the cavities 

 in the shell of the female. The males differ in every point 

 of detail, from the complemental males of S. vulgare, but 

 yet present so close a general resemblance, that a com- 

 parative description will be most convenient. 



The general shape of the whole animal is rather more 

 elongated, and I suspect flatter, but this latter point 

 could not be positively ascertained in dry specimens. 

 The entire length is greater, being in the largest specimen 

 TtVu (instead of at most 4V0), and the width, -$hv of an inch. 

 The orifice is not fimbriated ; the four bristly points over 

 the calcareous beads are absent. The whole outer in- 

 tegument is much thinner, owing evidently to its pro- 

 tected position, and is not covered by little bristles, but 

 with an extremely high power, minute points arranged in 

 transverse lines can be distinguished. The calcareous 

 beads, or rudimentary valves, are thin and regularly oval. 

 It is remarkable that in all the specimens, two on one 



