68 BULLETIN 120, UNITED STATES NATIONAL MUSEUM. 



this resemblance suggests the specific name. Cepedea dimidiata ioxm 

 zclleri has often much the same shape. The specimens in my material 

 show a coarsely alveolated (vacuolated) endosarc and an ectosarc 

 Avith much finer alveoles. The nuclei are not in good condition for 

 study. In the resting condition they are ellipsoidal. 



It is suggested that the reader turn at this point to the description 

 of ZellerieJla telmatohii, on page 131, for comparison with Frofo- 

 opalina xyster. The two forms are rather similar in general condi- 

 tion, except that in the former the flattening begun in P. xyster is car- 

 ried to the whole of the body. Whether or not the three species, P. 



ovoidea^ P. xyster^ and Z. tel- 



tmafohii, are actually genetically 

 related, they at least form a se- 

 ries which suggests how the Zel- 

 leriellas may have been derived 

 ; from the Protoopalinas. 

 ^ PROTOOPALINA AUSTRALIS, new 



S^ species. 



Type. — United States Na- 

 tional Museum Cat. No. 16619. 

 Host. — Hyla aurea (Lesson), 

 one exceedingly abundant in- 

 fection in United States Na- 

 tional Museum specimen No. 

 15478, from Wollongong, lUa- 

 ' to toJ 



wara. New South Wales, Aus- 

 tralia, collected January, 1840, 

 by the United States exploring 

 expedition. Another specimen 

 of this Hvla from King George 

 to to 



Sound, Australia, was opened, 

 but no Opalinids were found. 

 M easurements of an ordinary 

 individual, shown in figure JfO. — 



Fig. 39. — PnorooPALiNA xyster, x 460 diam- r ^i £ ^ -i r.^r^K 



ETERs. Length or body, 0.125 mm.; 



width of body, 0.022 mm.; 



length of nucleus, 0.015 mm. ; width of nucleus, 0.006 mm. ; diameter 



of endospherule, 0.002 mm. ; length of posterior process, 0.004 mm. to 



0.007 mm. in different individuals. 



This species is very different from Protoopallna hylarum which 

 Raff found in Ilyla aurea. It is but one-fourth as long, has elon- 

 gated instead of spherical nuclei, and bears a long, spinelike process 

 at the posterior end of the body. In shape of body it resembles 

 P. caudata discoglossi, but its nuclei are more elongated. It is more 



