i8o 



Fig. 5. LitJwbiiitnini forte, j ii;itur;il size. 



^(t. Vertical section showing in-current and ex-curreni 



canals. Natural size. 

 5/). Section of skeleton showing canals. 

 5£"-/. Monocrepid desnias, x 100. 

 5^'. Aniphitvle, X420. 



Fig. 6. Moiuiiilliiis pliiiiiosus in Ptithcisticlla. var. tiibulrthis. 

 if natural size. 

 6(1. Section of the same, f^ natural size. 

 6b. Part of an oscular tube, slightlv magnified. 

 6c. Monocrepid desma, x roo. 

 6t/. Oxea, x ico. 

 6(\ Stvle, X ICO. 



Fig. 7. Moiitiiitliiis pliiiiiosns on [\niiastirlla, sp. n, | natural 



size. 

 ya. Vertical section, § natural size. 

 yb. (At lower right corner of plate) a slender oxea from 



the dermal membrane, x 100 (very probably foreign).* 



* Note.- -The fact that the variety is designated as fig. 6 and the type as fig 

 7, while only the spicules oi the var. are figured, is due to the discovery of a 

 second specimen of the " type " leadmg to an alteration of the author's \ lews 

 after the plate had been printed off. 



[Published 27th May, 1903]. 



