292 IBLA AND SCALPELLUM. 



In looking for analogies to the facts here described, I 

 have already referred to the minute male Lerneidas which 

 cling to their females, — to the worm-like males of certain 

 Cephalopoda, parasitic on the females, — and to certain 

 Entozoons, in which the sexes cohere, or even are 

 organically blended by one extremity of their bodies. The 

 females in certain insects depart in structure, nearly or 

 quite as widely from the Order to which they belong, 

 as do these male parasitic Cirripedes ; some of these 

 females, like the males of the first three species of Scal- 

 pellum, do not feed, and some, I believe, have their 

 mouths in a rudimentary condition ; but in this latter 

 respect, we have, amongst the Rotifera, a closely analogous 

 case in the male of the Asplanchna of Gosse, which was 

 discovered by Mr. Bright well* to be entirely destitute of 

 mouth and stomach, exactly as I find to be the case with 

 the parasitic male of S. vulgare, and doubtless with its 

 two close allies. For any analogy to the existence of males, 

 complemental to hermaphrodites, we must look to the 

 vegetable kingdom. 



Finally, the simple fact of the diversity in the sexual 

 relations, displayed within the limits of the genera Ibla 

 and Scalpellum, appears to me eminently curious; we 

 have (1st) a female, with a male (or rarely two) perma- 

 nently attached to her, protected by her, and nourished by 

 any minute animals which may enter her sack ; (2d) a 

 female, with successive pairs of short-lived males, destitute 

 of mouth and stomach, inhabiting two pouches formed 

 on the under sides of her valves ; (3d) an hermaphrodite, 

 with from one or two, up to five or six similar short-lived 

 males without mouth or stomach, attached to one par- 

 ticular spot on each side of the orifice of the capitulum ; 

 and (4th) hermaphrodites, with occasionally one, two, or 

 three males, capable of seizing and devouring their prey 



* 'Annals of Natural History,' vol. ii, (2d series, 1848,) p. 153, PI. vi. 

 Mr. Dalrymple has published a very interesting paper on the same subject 

 in the 'Philosophical Transactions/ (p. 342,) 1849; and there is another 

 Memoir by Mr. Gosse in the 'Annals of Natural History,' vol. vi, (1850,) p. 18. 



