1888.] BROOD-POUCH OF RHtNODERMA D.VRVVINI. 23,') 



contracted and asymmetrical ; the orifices of the gular punch are 

 less modified than mii^lit have been expected (each is 7 mm. long), 

 and the whole Hoor of the mouth differs in no respect from that say 

 of a normal Cijstignathus. The larynx (/, fig. 4) is situated far 

 back, immediately behind a deep fold of the lining membrane of the 

 floor of the mouth. Its mucous membrane was slightly swollen 

 around the aditus ; but there were neither epiglottis nor other 

 accessory folds present, as might have been expected '. 



The brood-pouch of my specimen contained 1 1 larvae, that number 

 having been exceeded (12 and 15) by two of the five specimens 

 dissected by Espada. These little animals are represented in fig. 2 



Fig. 4. 



The floor of the mouth of Rhinodenna darwini, showing the tougue, larynx, 

 and the orifices of the guhir sac ; multiplied two and a half times. 



as they lay in life ; and it will be seen that they were, for the most 

 part, irregularly disposed. Espada asserts that in one of his 

 individuals the larvae (7 in number) were " einigermassen in zwei 

 parallelen Reihen angeordnet " ; he does not state, however, ia 

 what way the surfaces of the bodies of these or any of his specimens 

 were disposed respecting those of the parent. Examination of fig. 2 

 shows that, with the exception of two individuals on the parent's 

 left, all lay with their ventral faces in apposition with that of the 

 adult which bore them ; and it might appear from this that tiie 

 larvae are carried on their backs. These, it will be seen, were far 

 advanced in development and, with two exceptions, disposed with 

 their heads towards the neck of the sac, as though making their 

 way towards the exterior. From the positions in which they lay 

 it is tolerably certain that attempts were made by them to gain the 

 latter in their death-struggles ; and I imagine that the parent died 

 on its back, and that a stampede ensued, in which two of the unfor- 

 tunate 1 1 prisoners were overpowered before righting themselves. 



The larvae were, as in one of Espada's examples, unequally advanced 

 in development. In all, both fore and hind limbs were free, the 

 latter being webbed in three instances. Five of the 1 1 were caudate ; 

 and it is worthy of remark that those whose metamorphosis was 



1 Cf. P. Z. S. 1887, p. 499, and Spengel, op. cit. p. 497. 



