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PLATE I 



All the figures relate to Gromia Dujardiiii M. Schultze. 



Fig. 1. Oral region of a specimen with completely retracted protoplasm, and 

 the opening nearly closed, a, the finely granulated, non-striated portion 

 of the shell, which chiefly forms the nipple-shaped elevation when the 

 aperture is open (see Fig. 2). b, the portion of the shell which is radially 

 striated in optical section. The protoplasm in the opening of the shell 

 has a very distinct and longitudinally fibrillar, alveolar structure, c, 

 the large brown bodies contained in the protoplasm. x about 1000. 



Fig. 2. Aperture of a living specimen, from which a moderately large tuft of 

 protoplasm has emerged ; the protoplasm shows very distinctly a honey- 

 comb-like structure, and sends out a number of fine hyaline pseudopodia. 



Fig. 3, a. A pseudopodium in process of retraction, showing the alveolar 

 structure distinctly in two places, while the rest still appears quite 

 hyaline. 



Fig. 3, b-c. Two consecutive stages in the retraction of a pseudopodium. 

 The fine lateral branch * on Fig. 3, b, has already become relaxed and 

 wavy, and it contracted rapidly, becoming distinctly alveolar in the 

 process. It then united with the alveolar eminence ** to form the 

 alveolar appendage at the end of the pseudopodium in Fig. 3, c. 



