1803.] MICROSCOPICAL JOURNAL. 347 



Botli .'^oxual elements may be tmind in the same individuiil 

 sponge, but even in lierniaj)hrodites either the male or the 

 female element is in excess of the other ; in some species the 

 sexes are quite distinct. The ova develo()ed from Arch oocytes 

 or wandering amwboid cells, which increase in size and acquire 

 a store of reserve nourishment in the form of yoke granules. 

 At first they exhibit ameboid movements, but as they increase 

 in size they come to a resting stage. In Easponyia officmalis the 

 ova occur congregated in groups within the mesoderm, thus 

 presenting an early form of ovary. 



A New Sub-Stage. 



By GEO. WHITFIELD BROWN JR. 



NEW YORK. 



It was about B. C. 977 that "The Preacher" asked, "Is there 

 anything whereof it may be said, See, this is new?" (Eccl. I, 

 10). Novelty has so of:cn been honestly though mistakenly 

 claimed, that I hesitated about the adjective in the above cap- 

 tion ; but, if forgotten by the reader, I feel that he should be 

 willing to be reminded of a good thing. And I am quite sure 

 this sub-stage is a good thing for I have had one in continual 

 use for nearh' a year now, and speak only whereof I know. 

 The sub stage is scarcely second in importance to the stage it- 

 self of any first-class instrument, in the judgment of Dr. Dall- 

 inger (Carpenter, p. 169), and an efficient and economical one 

 is certainlv a great desideratum with any worker. 



The one now described and illustrated is fully shown actual 

 size in the accompanying drawing, partly perspective and partly 

 sectional, and its construction and operation can be therefrom 

 easily ascertained, aided by a few words of explanation. It was 

 made for me by Zentmayer of Philadelphia according to my 

 specifications and has given perfect satisfaction. In Fig. 1 the 

 bracket L, sliding on the tail-piece or moved by rack and pinion, 

 is the usual support of a sub-stage properly so called. The sub- 

 stage itself is secured thereon by a centering set-screw J, and 

 consists substantially of a double elbow with two arras, A and 

 B, each carrying a similar tubular holder for receiving accessory 

 apparatus, the former from above and the latter from below. 

 In the space between the upper and lower holders is situated a 



